Body Control Module Page 12J–1

Page 12J–1

Section 12J

Body Control Module

ATTENTION

Before performing any service operation or other procedure described in this section, refer to Section 00

Warnings, Cautions and Notes for correct w orkshop practices with regard to safety and/or property damage.

1 General Information.............................................................................................................................14

1.1 Abbreviations....................................................................................................................................................... 14

1.2 Body Control Module........................................................................................................................................... 15

1.3 Body Control Module Models............................................................................................................................. 16

1.4 Body Control Module Features........................................................................................................................... 17

Feature Table Key................................................................................................................................................ 17

Feature Table........................................................................................................................................................ 17

2 System Operation.................................................................................................................................21

2.1 Body Control Module Operating Modes ............................................................................................................ 21

Battery Saver Mode.............................................................................................................................................. 21

Pre-delivery Mode................................................................................................................................................ 21

2.2 Serial Data Communication – V6........................................................................................................................ 22

System Overview ................................................................................................................................................. 22

V6 Serial Data Block Diagram.......................................................................................................................... 23

The GM LAN Bus System ................................................................................................................................ 24

UART Communications.................................................................................................................................... 24

Serial Data Bus ................................................................................................................................................ 24

Data Bus Device Polling................................................................................................................................... 25

Tech 2 and the Data Link Connector................................................................................................................ 25

Inputs and Outputs.............................................................................................................................................. 25

GM LAN Data Bus............................................................................................................................................ 25

Serial Data Signal – Primary UART.................................................................................................................. 25

Serial Data Signals – Secondary and Tertiary UART....................................................................................... 25

Data Bus Device Polling................................................................................................................................... 26

Data Messages ................................................................................................................................................ 26

Pow ertrain Interface Module............................................................................................................................... 26

2.3 Serial Data Communication – GEN III V8........................................................................................................... 27

System Overview ................................................................................................................................................. 27

GEN III V8 Serial Data Block Diagram............................................................................................................. 28

UART and Class 2 Serial Data Bus.................................................................................................................. 29

Data Bus Device Polling................................................................................................................................... 29

Tech 2 and the Data Link Connector................................................................................................................ 29

Inputs and Outputs.............................................................................................................................................. 30

Class 2 Serial Data Signal................................................................................................................................ 30

Serial Data Signal – Primary UART.................................................................................................................. 30

Serial Data Signal – Secondary and Tertiary UART......................................................................................... 30

Data Bus Device Polling................................................................................................................................... 30

Data Messages ................................................................................................................................................ 30

Pow ertrain Interface Module............................................................................................................................... 30

Techline

Body Control Module Page 12J–2

Page 12J–2

2.4 Serial Data Communication – GEN IV V8........................................................................................................... 31

System Overview ................................................................................................................................................. 31

GEN IV V8 Serial Data Block Diagram............................................................................................................. 32

The GM LAN Bus System ................................................................................................................................ 33

UART Communications.................................................................................................................................... 33

Serial Data Bus ................................................................................................................................................ 33

Data Bus Device Polling................................................................................................................................... 34

Tech 2 and the Data Link Connector................................................................................................................ 34

Inputs and Outputs.............................................................................................................................................. 34

GM LAN Data Bus............................................................................................................................................ 34

Serial Data Signal – Primary UART.................................................................................................................. 34

Serial Data Signals – Secondary and Tertiary UART....................................................................................... 34

Data Bus Device Polling................................................................................................................................... 35

Data Messages ................................................................................................................................................ 35

Pow ertrain Interface Module............................................................................................................................... 35

2.5 Remote Receiver / Key ........................................................................................................................................ 36

System Operation ................................................................................................................................................ 36

Unlocking.......................................................................................................................................................... 36

Locking............................................................................................................................................................. 36

Rear Compartment Lid Release....................................................................................................................... 36

Remote Coded Key Battery Failure.................................................................................................................. 36

Circuit Operation.................................................................................................................................................. 37

2.6 Accessory Power Control ................................................................................................................................... 38

System Operation ................................................................................................................................................ 38

Accessory Relay Shutdown Options................................................................................................................. 38

Wiper Control of the Accessory Relay.............................................................................................................. 38

Circuit Operation.................................................................................................................................................. 38

Radio On and Ignition Switch Input.................................................................................................................. 39

2.7 Central Door Locking .......................................................................................................................................... 40

System Operation ................................................................................................................................................ 40

Door Locking.................................................................................................................................................... 40

Door Unlocking................................................................................................................................................. 40

Deadlocking...................................................................................................................................................... 40

Single-stage and Two-stage Unlocking............................................................................................................ 41

System Check ...................................................................................................................................................... 42

Key Locking...................................................................................................................................................... 42

Remote Coded Key Check............................................................................................................................... 42

Deadlocking Check .......................................................................................................................................... 42

Door-lock Failure Warning................................................................................................................................ 42

Auto Door-lock in Drive .................................................................................................................................... 43

Overheating Prevention.................................................................................................................................... 43

Functional Description of Door Locking/Unlocking Operation........................................................................... 43

Functional Diagram of Door Locking/Unlocking Operation............................................................................... 45

Circuit Operation.................................................................................................................................................. 46

Unlocking.......................................................................................................................................................... 46

Locking............................................................................................................................................................. 47

Door Input Signals............................................................................................................................................ 48

2.8 Rear Compartment Lid Release.......................................................................................................................... 49

System Operation ................................................................................................................................................ 49

Circuit Operation.................................................................................................................................................. 49

Power Supplies ................................................................................................................................................ 49

Inputs ............................................................................................................................................................... 49

Outputs............................................................................................................................................................. 50

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Page 12J–3

2.9 Theft Deterrent System........................................................................................................................................ 51

System Operation ................................................................................................................................................ 51

V6 and GEN IV V8 Engine ............................................................................................................................... 51

GEN III V8 Engine............................................................................................................................................ 51

Battery.............................................................................................................................................................. 52

Security Status Indicator................................................................................................................................... 52

Circuit Operation.................................................................................................................................................. 53

Power Supplies ................................................................................................................................................ 53

Turn Signal Lamp Power.................................................................................................................................. 53

Inputs ............................................................................................................................................................... 53

Outputs............................................................................................................................................................. 54

2.10 Entry Deterrent System....................................................................................................................................... 55

System Operation ................................................................................................................................................ 55

Arming the System........................................................................................................................................... 55

Triggered Operation......................................................................................................................................... 55

Disarming Procedure........................................................................................................................................ 56

Multi-function Display (MFD) Trigger Point Displays ........................................................................................ 56

Remote Rear Compartment Release ............................................................................................................... 56

Loss of Vehicle Battery Power .......................................................................................................................... 56

Circuit Operation.................................................................................................................................................. 57

Power Supplies ................................................................................................................................................ 57

Inputs ............................................................................................................................................................... 57

Outputs............................................................................................................................................................. 58

2.11 Power Window System ....................................................................................................................................... 59

System Operation ................................................................................................................................................ 59

System Active................................................................................................................................................... 59

System Inactive................................................................................................................................................ 59

Automatic Down Operation of Front Windows.................................................................................................. 59

Lockout Switch................................................................................................................................................. 60

Circuit Operation.................................................................................................................................................. 60

Ignition ON Input Signal ................................................................................................................................... 60

Driver and Front Passenger Window-down Circuit........................................................................................... 61

Driver and Front Passenger Window-up Circuit................................................................................................ 61

Rear Passenger Window Operation................................................................................................................. 61

2.12 Wiper System Intermittent Function .................................................................................................................. 62

System Operation ................................................................................................................................................ 62

Level 1 Vehicles............................................................................................................................................... 62

Level 2 and 3 Vehicles and AWD Wagon......................................................................................................... 62

Rear Wiper Operation AWD Wagon................................................................................................................. 62

Circuit Operation.................................................................................................................................................. 63

Intermittent Wiper Switch.................................................................................................................................. 63

Wiper Dwell Controller...................................................................................................................................... 63

Vehicle Speed and Reverse Gear.................................................................................................................... 63

Window Washer Switch.................................................................................................................................... 64

Rear Wiper Switch............................................................................................................................................ 64

Rear Washer Switch......................................................................................................................................... 64

2.13 Dome Lamp Delay Control.................................................................................................................................. 65

System Operation ................................................................................................................................................ 65

Level 1 Vehicles............................................................................................................................................... 65

Level 2 and 3 Vehicles ..................................................................................................................................... 65

Circuit Operation – Level 1 Vehicles.................................................................................................................. 66

Inputs ............................................................................................................................................................... 66

Circuit Operation – Level 2 and 3 Vehicles........................................................................................................ 67

Inputs ............................................................................................................................................................... 67

Body Control Module Page 12J–4

Page 12J–4

2.14 Automatic Lamp Control..................................................................................................................................... 68

System Operation ................................................................................................................................................ 68

Automatic Lights On......................................................................................................................................... 68

Automatic Lights Off......................................................................................................................................... 68

Approach Illumination....................................................................................................................................... 69

Circuit Operation – Lights On............................................................................................................................. 69

Inputs ............................................................................................................................................................... 69

Power Supplies ................................................................................................................................................ 70

Ground Circuits ................................................................................................................................................ 70

Circuit Operation – Lights Off............................................................................................................................. 70

Inputs ............................................................................................................................................................... 70

Power Supplies ................................................................................................................................................ 71

Ground Circuits ................................................................................................................................................ 71

2.15 Instrument Dimming Control .............................................................................................................................. 72

System Operation ................................................................................................................................................ 72

Circuit Operation.................................................................................................................................................. 72

Inputs ............................................................................................................................................................... 73

2.16 Air-conditioning Interface ................................................................................................................................... 74

System Operation ................................................................................................................................................ 74

Circuit Operation.................................................................................................................................................. 74

Inputs ............................................................................................................................................................... 74

Outputs............................................................................................................................................................. 74

Blower Motor.................................................................................................................................................... 74

2.17 Occupant Protection System Deployment Vehicle Shutdown......................................................................... 75

System Operation ................................................................................................................................................ 75

OPS Deployment Signals................................................................................................................................. 75

2.18 Priority Key System............................................................................................................................................. 76

Operating Parameters ......................................................................................................................................... 76

Parameter Checks............................................................................................................................................ 76

Circuit Operation.................................................................................................................................................. 77

2.19 Pow er Antenna Control....................................................................................................................................... 78

System Operation ................................................................................................................................................ 78

Power Antenna................................................................................................................................................. 78

Circuit Operation.................................................................................................................................................. 79

Antenna Up Switch Input Signal....................................................................................................................... 79

Antenna Up Memory Height............................................................................................................................. 79

Antenna Down.................................................................................................................................................. 79

Antenna Auto-down.......................................................................................................................................... 79

2.20 Heated Rear Window ........................................................................................................................................... 80

System Operation ................................................................................................................................................ 80

Delay Timer...................................................................................................................................................... 80

Circuit Operation.................................................................................................................................................. 80

Heated Rear Window Switch Input Signal........................................................................................................ 80

2.21 Rear Lamp Failure Warning System................................................................................................................... 81

System Operation ................................................................................................................................................ 81

Components Monitored.................................................................................................................................... 81

Circuit Operation.................................................................................................................................................. 82

Ground Circuit Monitoring................................................................................................................................. 82

Rear Lamp Failure Warning Lamp ................................................................................................................... 82

Inputs ............................................................................................................................................................... 82

2.22 Hazard Lamp Control........................................................................................................................................... 83

System Operation ................................................................................................................................................ 83

Circuit Operation.................................................................................................................................................. 83

Body Control Module Page 12J–5

Page 12J–5

3 Wiring Diagrams and Connector Charts............................................................................................84

3.1 Wiring Diagrams – V6.......................................................................................................................................... 84

Ignition Key, RX Sensor, Common Power and Grounds.................................................................................. 84

Accessory Power Circuit..................................................................................................................................... 85

UART and GM LAN Communications – 5 Speed Automatic............................................................................. 86

UART and GM LAN Communications – 4 Speed Automatic with ESP............................................................ 87

UART and GM LAN Communications – 4 Speed Automatic with without ESP .............................................. 88

Central Door Locking .......................................................................................................................................... 89

Entry Deterrent, Warning Horns and Rear Compartment Solenoid................................................................. 90

Entry Deterrent, Warning Horns and Rear Lift Glass Solenoid – AWD Wagon only...................................... 91

Power Windows – Two Door Vehicles............................................................................................................... 92

Power Windows – Four Door Vehicles .............................................................................................................. 93

Wiper Systems Intermittent Function – Utility, Regular & Crew Cab and Sedan, Level 1............................. 94

Wiper Systems Intermittent Function – Sedan, Level 2 and 3 ......................................................................... 95

Wiper Systems Intermittent Function – Wagon, Level 1................................................................................... 96

Wiper Systems Intermittent Function – Wagon, Level 2................................................................................... 97

Wiper Systems Intermittent Function – AWD Wagon, Level 1......................................................................... 98

Wiper Systems Intermittent Function – AWD Wagon, Level 2......................................................................... 99

Dome Lamp Delay Control – Utility, Regular & Crew Cab, Level 1................................................................ 100

Dome Lamp Delay Control – Sedan and Wagon, Level 1............................................................................... 101

Dome Lamp Delay Control – Sedan and Wagon, Level 2 and 3..................................................................... 102

Automatic Lamp Control – Level 1................................................................................................................... 103

Automatic Lamp Control – Level 2 and 3......................................................................................................... 104

HVAC – Heated Rear Window and Air conditioning Interface – Level 1........................................................ 105

Radio and Pow er Antenna Control – Level 1................................................................................................... 106

Radio and Pow er Antenna Control – Level 2 and 3 ........................................................................................ 106

Rear Lamp Failure System – Level 3................................................................................................................ 107

Hazard Lamp Control, Theft / Turn Signal Lamp Flasher............................................................................... 108

3.2 Connector Charts – V6 ...................................................................................................................................... 109

3.3 Wiring Diagrams – GEN III V8 ........................................................................................................................... 113

Ignition Key, RX Sensor, Common Power and Grounds................................................................................ 113

Accessory Power Circuit................................................................................................................................... 114

UART and Class 2 Communications................................................................................................................ 115

Central Door Locking ........................................................................................................................................ 116

Entry Deterrent, Warning Horns and Rear Compartment Solenoid............................................................... 117

Entry Deterrent, Warning Horns and Rear Lift Glass Solenoid – AWD Wagon Only ................................... 118

Power Windows – Two Door Vehicles............................................................................................................. 119

Power Windows – Four Door Vehicles ............................................................................................................ 120

Wiper Systems Intermittent Function – Utility, Regular & Crew Cab and Sedan, Level 1........................... 121

Wiper Systems Intermittent Function – Sedan, Level 2 and 3 ....................................................................... 122

Wiper Systems Intermittent Function – Wagon, Level 1................................................................................. 123

Wiper Systems Intermittent Function – Wagon, Level 2 and 3...................................................................... 124

Wiper Systems Intermittent Function – AWD Wagon, Level 2....................................................................... 125

Dome Lamp Delay Control – Utility, Regular & Crew Cab, Level 1................................................................ 126

Dome Lamp Delay Control – Sedan and Wagon, Level 1............................................................................... 127

Dome Lamp Delay Control – Sedan and Wagon, Level 2 and 3..................................................................... 128

Dome Lamp Delay Control – Coupe, Level 2 and 3......................................................................................... 129

Automatic Lamp Control – Level 1................................................................................................................... 130

Automatic Lamp Control – Level 2 and 3......................................................................................................... 131

HVAC – Heated Rear Window and Air conditioning Interface – Level 1........................................................ 132

Radio and Pow er Antenna Control – Level 1................................................................................................... 133

Radio and Pow er Antenna Control – Level 2 and 3 ........................................................................................ 133

Rear Lamp Failure System – Level 3................................................................................................................ 134

Hazard Lamp Control, Theft / Turn Signal Lamp Flasher............................................................................... 135

3.4 Connector Charts – GEN III V8.......................................................................................................................... 136

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3.5 Wiring Diagrams – GEN IV V8........................................................................................................................... 140

Ignition Key, RX Sensor, Common Power and Grounds................................................................................ 140

Accessory Power Circuit................................................................................................................................... 141

UART and GM LAN Communications – 4 Speed Automatic with ESP.......................................................... 142

Central Door Locking ........................................................................................................................................ 143

Entry Deterrent, Warning Horns and Rear Compartment Solenoid............................................................... 144

Entry Deterrent, Warning Horns and Rear Lift Glass Solenoid – AWD Wagon only.................................... 145

Power Windows – Two Door Vehicles............................................................................................................. 146

Power Windows – Four Door Vehicles ............................................................................................................ 147

Wiper Systems Intermittent Function – Utility, Regular & Crew Cab and Sedan, Level 1........................... 148

Wiper Systems Intermittent Function – Sedan, Level 2 and 3 ....................................................................... 149

Wiper Systems Intermittent Function – Wagon, Level 1................................................................................. 150

Wiper Systems Intermittent Function – Wagon, Level 2................................................................................. 151

Wiper Systems Intermittent Function – AWD Wagon, Level 1....................................................................... 152

Wiper Systems Intermittent Function – AWD Wagon, Level 2....................................................................... 153

Dome Lamp Delay Control – Utility, Regular & Crew Cab, Level 1................................................................ 154

Dome Lamp Delay Control – Sedan and Wagon, Level 1............................................................................... 155

Dome Lamp Delay Control – Sedan and Wagon, Level 2 and 3..................................................................... 156

Automatic Lamp Control – Level 1................................................................................................................... 157

Automatic Lamp Control – Level 2 and 3......................................................................................................... 158

HVAC – Heated Rear Window and Air conditioning Interface – Level 1........................................................ 159

Radio and Pow er Antenna Control – Level 1................................................................................................... 160

Radio and Pow er Antenna Control – Level 2 and 3 ........................................................................................ 160

Rear Lamp Failure System – Level 3................................................................................................................ 161

Hazard Lamp Control, Theft / Turn Signal Lamp Flasher............................................................................... 162

3.6 Connector Charts – GEN IV V8......................................................................................................................... 163

3.7 Connector Information ...................................................................................................................................... 167

BCM Location and Wiring Connectors ............................................................................................................ 167

BCM Connector Pin Identification.................................................................................................................... 167

Legend – Circuit Type .................................................................................................................................... 170

Explanation of Terms ..................................................................................................................................... 170

4 Tech 2 Information .............................................................................................................................171

4.1 Connecting Tech 2 For System Diagnosis ...................................................................................................... 171

4.2 Tech 2 Test Modes and Displays...................................................................................................................... 172

4.3 Normal Mode...................................................................................................................................................... 173

4.4 Diagnostic Trouble Codes ................................................................................................................................ 174

Read DTC Information....................................................................................................................................... 174

Read Alarm Codes............................................................................................................................................. 174

Clear DTC and Alarm Codes ............................................................................................................................. 174

4.5 Data Display ....................................................................................................................................................... 175

Inputs and Outputs............................................................................................................................................ 175

BCM Internal Status........................................................................................................................................... 177

Serial Data Inputs............................................................................................................................................... 178

Priority 1 User Settings ..................................................................................................................................... 178

Priority 2 User Settings ..................................................................................................................................... 179

Alarm / Theft Deterrent...................................................................................................................................... 179

Central Door Locking ........................................................................................................................................ 180

Power Windows................................................................................................................................................. 181

Wipers................................................................................................................................................................. 181

Headlamps.......................................................................................................................................................... 182

Instrument Illumination..................................................................................................................................... 182

Interior Illumination ........................................................................................................................................... 183

Rear Lamp Failure.............................................................................................................................................. 183

Air-conditioning Interface ................................................................................................................................. 184

Antenna............................................................................................................................................................... 184

System Identification......................................................................................................................................... 185

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4.6 Snapshot ............................................................................................................................................................ 186

4.7 Miscellaneous Tests.......................................................................................................................................... 187

Lamps ................................................................................................................................................................. 187

Interior Lamp.................................................................................................................................................. 187

Headlamps..................................................................................................................................................... 188

Indicators........................................................................................................................................................ 188

Instrument Illumination................................................................................................................................... 188

Auto Lights On................................................................................................................................................ 188

Rear Lamp Bulb Fail....................................................................................................................................... 189

Rear Stop Lamp Bulb Fail .............................................................................................................................. 189

Rear Lamp Fuse Fail...................................................................................................................................... 189

Data Bus Isolator ............................................................................................................................................... 190

Central Locking.................................................................................................................................................. 190

Rear Compartment............................................................................................................................................. 190

Wipers................................................................................................................................................................. 191

Front Wipers................................................................................................................................................... 191

Rear Wiper..................................................................................................................................................... 191

Power Windows................................................................................................................................................. 192

Driver’s Window Auto-down............................................................................................................................ 192

Front Passenger’s Window Auto-down........................................................................................................... 192

Power Window Relay ..................................................................................................................................... 193

Antenna............................................................................................................................................................... 193

Horn .................................................................................................................................................................... 193

Interior Illumination Relay................................................................................................................................. 194

Accessory Relay ................................................................................................................................................ 194

Security System................................................................................................................................................. 195

Security LED .................................................................................................................................................. 195

Theft Deterrent Horn ...................................................................................................................................... 195

Key Priority..................................................................................................................................................... 195

4.8 Program.............................................................................................................................................................. 196

User Settings...................................................................................................................................................... 196

Instrument Illumination................................................................................................................................... 196

Options............................................................................................................................................................... 197

Antenna Height Memory................................................................................................................................. 197

Set Key to Priority 1........................................................................................................................................... 197

Learn BCM Settings........................................................................................................................................... 197

Program Learnt BCM Settings.......................................................................................................................... 197

4.9 Security............................................................................................................................................................... 198

BCM Link to ECM/PCM/PIM............................................................................................................................... 198

Security Information.......................................................................................................................................... 199

Program.............................................................................................................................................................. 199

5 Diagnostics.........................................................................................................................................200

5.1 Introduction........................................................................................................................................................ 200

5.2 Prerequisites to Diagnosis and Troubleshooting........................................................................................... 201

Preliminary System Requirements................................................................................................................... 201

Pre-delivery Mode.............................................................................................................................................. 201

Safety Requirements ......................................................................................................................................... 201

Equipment and Checking.................................................................................................................................. 201

5.3 Diagnostic Trouble Code Definitions............................................................................................................... 202

Current Diagnostic Trouble Codes................................................................................................................... 202

History Diagnostic Trouble Codes................................................................................................................... 202

5.4 Description of Diagnostic Trouble Codes ....................................................................................................... 203

Multiple Diagnostic Trouble Code Fault Condition......................................................................................... 203

5.5 Intermittent Fault Conditions............................................................................................................................ 204

Description......................................................................................................................................................... 204

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5.6 Diagnostic System Check................................................................................................................................. 205

Description......................................................................................................................................................... 205

Test Description ............................................................................................................................................. 205

Diagnostic Table............................................................................................................................................. 205

5.7 Symptoms Diagnostics Table........................................................................................................................... 206

5.8 Diagnostic Trouble Code List........................................................................................................................... 207

5.9 Serial Data Communications ............................................................................................................................ 209

DTC Description................................................................................................................................................. 209

Circuit Description............................................................................................................................................. 209

Diagnostic Table................................................................................................................................................ 209

Test Description ............................................................................................................................................. 209

Diagnostic Table Notes .................................................................................................................................. 209

Diagnostic Table............................................................................................................................................. 210

5.10 Remote Receiver / Key ...................................................................................................................................... 213

Circuit Description............................................................................................................................................. 213

Remote Coded Key Battery Failure................................................................................................................ 213

Preliminary Diagnostic Table............................................................................................................................ 213

Test Description ............................................................................................................................................. 213

Diagnostic Table Notes .................................................................................................................................. 213

Diagnostic Table............................................................................................................................................. 214

Main Diagnostic Table....................................................................................................................................... 215

Test Description ............................................................................................................................................. 215

Diagnostic Table Notes .................................................................................................................................. 215

Diagnostic Table............................................................................................................................................. 215

5.11 Accessory Power Control ................................................................................................................................. 216

Circuit Description............................................................................................................................................. 216

Diagnostic Table................................................................................................................................................ 216

Test Description ............................................................................................................................................. 216

Diagnostic Table Notes .................................................................................................................................. 216

Diagnostic Table............................................................................................................................................. 217

5.12 Central Door Locking ........................................................................................................................................ 219

System Overview ............................................................................................................................................... 219

Unlocking the Doors Using the Driver’s Door Micro switch............................................................................. 219

Locking the Doors Using the Driver’s Door Micro switch................................................................................ 219

Door Locking System Test Overview............................................................................................................... 219

Diagnostic Trouble Codes ................................................................................................................................ 220

Conditions for Setting the DTC....................................................................................................................... 220

Conditions for Clearing the DTC..................................................................................................................... 220

Preliminary Diagnostic Table............................................................................................................................ 220

Test Description ............................................................................................................................................. 220

Diagnostic Table Notes .................................................................................................................................. 220

Diagnostic Table............................................................................................................................................. 221

Unlocking the Driver’s Door Using the Door Lock Diagnostic Table............................................................ 223

Test Description ............................................................................................................................................. 223

Diagnostic Table Notes .................................................................................................................................. 223

Diagnostic Table............................................................................................................................................. 223

Unlocking the Driver’s Door Using the Door Snib Diagnostic Table............................................................. 225

Test Description ............................................................................................................................................. 225

Diagnostic Table Notes .................................................................................................................................. 225

Diagnostic Table............................................................................................................................................. 225

Unlocking / Locking the Front Passenger’s Doors Using the Door Snib Diagnostic Table........................ 227

Test Description ............................................................................................................................................. 227

Diagnostic Table Notes .................................................................................................................................. 227

Diagnostic Table............................................................................................................................................. 227

Body Control Module Page 12J–9

Page 12J–9

Deadlocking the Vehicle’s Doors Diagnostic Table........................................................................................ 229

Test Description ............................................................................................................................................. 229

Diagnostic Table Notes .................................................................................................................................. 229

Diagnostic Table............................................................................................................................................. 229

Auto-door Locking (Gearshift In and Out of Park Position) Diagnostic Table ............................................. 230

Test Description ............................................................................................................................................. 230

Diagnostic Table Notes .................................................................................................................................. 230

Diagnostic Table............................................................................................................................................. 230

Door Ajar Switches Diagnostic Table .............................................................................................................. 231

Test Description ............................................................................................................................................. 231

Diagnostic Table Notes .................................................................................................................................. 231

Diagnostic Table............................................................................................................................................. 232

Rear Compartment Release Diagnostic Table................................................................................................. 233

Test Description ............................................................................................................................................. 233

Diagnostic Table Notes .................................................................................................................................. 233

Diagnostic Table............................................................................................................................................. 233

5.13 Theft Deterrent System...................................................................................................................................... 235

Circuit Description............................................................................................................................................. 235

V6 and GEN IV V8 Engines............................................................................................................................ 235

GEN III V8 Engine.......................................................................................................................................... 235

Diagnostic Table................................................................................................................................................ 236

Test Description ............................................................................................................................................. 236

Diagnostic Table Notes .................................................................................................................................. 236

Diagnostic Table............................................................................................................................................. 236

5.14 Entry Deterrent System..................................................................................................................................... 239

Circuit Description............................................................................................................................................. 239

Preliminary Diagnostic Table............................................................................................................................ 239

Test Description ............................................................................................................................................. 239

Diagnostic Table Notes .................................................................................................................................. 239

Diagnostic Table............................................................................................................................................. 240

Main Diagnostic Table....................................................................................................................................... 242

Test Description ............................................................................................................................................. 242

Diagnostic Table Notes .................................................................................................................................. 242

Diagnostic Table............................................................................................................................................. 242

Horn Diagnostic Table....................................................................................................................................... 244

Test Description ............................................................................................................................................. 244

Diagnostic Table Notes .................................................................................................................................. 244

Diagnostic Table............................................................................................................................................. 244

5.15 Power Window System ..................................................................................................................................... 246

Circuit Description............................................................................................................................................. 246

Introduction........................................................................................................................................................ 246

Preliminary Diagnostic Table............................................................................................................................ 246

Test Description ............................................................................................................................................. 246

Diagnostic Table Notes .................................................................................................................................. 247

Diagnostic Table............................................................................................................................................. 247

Main Power Diagnostic Table........................................................................................................................... 249

Test Description ............................................................................................................................................. 249

Diagnostic Table Notes .................................................................................................................................. 249

Diagnostic Table............................................................................................................................................. 249

Front Window Diagnostic Table....................................................................................................................... 251

Test Description ............................................................................................................................................. 251

Diagnostic Table Notes .................................................................................................................................. 251

Diagnostic Table............................................................................................................................................. 251

Rear Windows Diagnostic Table ...................................................................................................................... 254

Test Description ............................................................................................................................................. 254

Diagnostic Table Notes .................................................................................................................................. 254

Diagnostic Table............................................................................................................................................. 254

Body Control Module Page 12J–10

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5.16 Wiper Systems Intermittent Function .............................................................................................................. 257

Circuit Description............................................................................................................................................. 257

Preliminary Diagnostic Table – Front Wiper, Level 1...................................................................................... 257

Test Description ............................................................................................................................................. 257

Diagnostic Table............................................................................................................................................. 257

Preliminary Diagnostic Table – Front Wiper, Level 2 and 3 ........................................................................... 259

Test Description ............................................................................................................................................. 259

Diagnostic Table............................................................................................................................................. 259

Preliminary Diagnostic Table – Rear Wiper, Wagon....................................................................................... 261

Test Description ............................................................................................................................................. 261

Diagnostic Table Notes .................................................................................................................................. 261

Diagnostic Table............................................................................................................................................. 262

Preliminary Diagnostic Table – Rear Wiper, AWD Wagon.............................................................................. 263

Test Description ............................................................................................................................................. 263

Diagnostic Table............................................................................................................................................. 263

Intermittent Diagnostic Table – Front Wipers, Level 1 ................................................................................... 264

Test Description ............................................................................................................................................. 264

Diagnostic Table Notes .................................................................................................................................. 264

Diagnostic Table............................................................................................................................................. 264

Intermittent Diagnostic Table – Front Wiper, Level 2 and 3........................................................................... 266

Test Description ............................................................................................................................................. 266

Diagnostic Table Notes .................................................................................................................................. 266

Diagnostic Table............................................................................................................................................. 266

Intermittent Diagnostic Table – Rear Wiper, Wagon....................................................................................... 269

Test Description ............................................................................................................................................. 269

Diagnostic Table Notes .................................................................................................................................. 269

Diagnostic Table............................................................................................................................................. 269

Intermittent Diagnostic Table – Rear Wiper, AWD Wagon ............................................................................. 271

Test Description ............................................................................................................................................. 271

Diagnostic Table Notes .................................................................................................................................. 271

Diagnostic Table............................................................................................................................................. 271

Road Speed Diagnostic Table........................................................................................................................... 272

Test Description ............................................................................................................................................. 272

Diagnostic Table Notes .................................................................................................................................. 272

Diagnostic Table............................................................................................................................................. 272

5.17 Dome Lamp Delay Control................................................................................................................................ 273

Circuit Description............................................................................................................................................. 273

Level 1 vehicles.............................................................................................................................................. 273

Level 2 and 3 vehicles.................................................................................................................................... 273

Coupe............................................................................................................................................................. 273

All vehicles ..................................................................................................................................................... 273

Battery Saver Mode........................................................................................................................................ 273

Preliminary Diagnostic Table – Utility and Regular & Crew Cab Level 1...................................................... 274

Test Description ............................................................................................................................................. 274

Diagnostic Table Notes .................................................................................................................................. 274

Diagnostic Table............................................................................................................................................. 274

Preliminary Diagnostic Table – Sedan and Wagon, Level 1........................................................................... 276

Test Description ............................................................................................................................................. 276

Diagnostic Table Notes .................................................................................................................................. 276

Diagnostic Table............................................................................................................................................. 276

Preliminary Diagnostic Table – Sedan and Wagon, Level 2 and 3 ................................................................ 278

Test Description ............................................................................................................................................. 278

Diagnostic Table Notes .................................................................................................................................. 278

Diagnostic Table............................................................................................................................................. 278

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Preliminary Diagnostic Table – Coupe............................................................................................................. 280

Test Description ............................................................................................................................................. 280

Diagnostic Table Notes .................................................................................................................................. 280

Diagnostic Table............................................................................................................................................. 280

Main Diagnostic Table – Utility and Regular & Crew Cab Level 1 ................................................................. 282

Test Description ............................................................................................................................................. 282

Diagnostic Table Notes .................................................................................................................................. 282

Diagnostic Table............................................................................................................................................. 282

Main Diagnostic Table – Sedan and Wagon, Level 1...................................................................................... 284

Test Description ............................................................................................................................................. 284

Diagnostic Table Notes .................................................................................................................................. 284

Diagnostic Table............................................................................................................................................. 284

Main Diagnostic Table – Sedan and Wagon, Level 2 and 3............................................................................ 286

Test Description ............................................................................................................................................. 286

Diagnostic Table Notes .................................................................................................................................. 286

Diagnostic Table............................................................................................................................................. 286

Main Diagnostic Table – Coupe........................................................................................................................ 288

Test Description ............................................................................................................................................. 288

Diagnostic Table Notes .................................................................................................................................. 288

Diagnostic Table............................................................................................................................................. 288

5.18 Automatic Lamp Control................................................................................................................................... 290

Circuit Description............................................................................................................................................. 290

Automatic Lamps Off...................................................................................................................................... 290

Automatic Lamps On...................................................................................................................................... 290

Adjustment ..................................................................................................................................................... 290

Approach Illumination..................................................................................................................................... 290

Preliminary Diagnostic Table............................................................................................................................ 291

Test Description ............................................................................................................................................. 291

Diagnostic Table............................................................................................................................................. 291

Sunload Sensor Diagnostic Table.................................................................................................................... 292

Test Description ............................................................................................................................................. 292

Diagnostic Table Notes .................................................................................................................................. 292

Diagnostic Table............................................................................................................................................. 292

Lamps On / Lamps Off Diagnostic Table......................................................................................................... 294

Test Description ............................................................................................................................................. 294

Diagnostic Table Notes .................................................................................................................................. 294

Diagnostic Table............................................................................................................................................. 294

5.19 Instrument Dimming Control ............................................................................................................................ 296

Circuit Description............................................................................................................................................. 296

Preliminary Diagnostic Table............................................................................................................................ 296

Test Description ............................................................................................................................................. 296

Diagnostic Table............................................................................................................................................. 296

Main Diagnostic Table....................................................................................................................................... 297

Test Description ............................................................................................................................................. 297

Diagnostic Table Notes .................................................................................................................................. 297

Diagnostic Table............................................................................................................................................. 297

5.20 Air-conditioning Interface ................................................................................................................................. 298

Circuit Description............................................................................................................................................. 298

Preliminary Diagnostic Table............................................................................................................................ 298

Test Description ............................................................................................................................................. 298

Diagnostic Table............................................................................................................................................. 299

Main Diagnostic Table....................................................................................................................................... 300

Test Description ............................................................................................................................................. 300

Diagnostic Table Notes .................................................................................................................................. 300

Diagnostic Table............................................................................................................................................. 300

Body Control Module Page 12J–12

Page 12J–12

5.21 OPS Deployment Vehicle Shutdown................................................................................................................ 302

Circuit Description............................................................................................................................................. 302

Diagnostic Table................................................................................................................................................ 302

Test Description ............................................................................................................................................. 302

Diagnostic Table Notes .................................................................................................................................. 302

Diagnostic Table............................................................................................................................................. 303

5.22 Priority Key System........................................................................................................................................... 304

Circuit Description............................................................................................................................................. 304

Diagnostic Table................................................................................................................................................ 304

Test Description ............................................................................................................................................. 304

Diagnostic Table Notes .................................................................................................................................. 304

Diagnostic Table............................................................................................................................................. 305

5.23 Pow er Antenna Control..................................................................................................................................... 307

Circuit Description............................................................................................................................................. 307

Diagnostic Table................................................................................................................................................ 307

Test Description ............................................................................................................................................. 307

Diagnostic Table Notes .................................................................................................................................. 307

Diagnostic Table............................................................................................................................................. 307

5.24 Heated Rear Window ......................................................................................................................................... 308

Circuit Description............................................................................................................................................. 308

Preliminary Diagnostic Table............................................................................................................................ 308

Test Descriptions............................................................................................................................................ 308

Diagnostic Table............................................................................................................................................. 308

Main Diagnostic Table....................................................................................................................................... 309

Test Descriptions............................................................................................................................................ 309

Diagnostic Table Notes .................................................................................................................................. 309

Diagnostic Table............................................................................................................................................. 309

5.25 Rear Lamp Failure Warning System................................................................................................................. 311

Circuit Description............................................................................................................................................. 311

Preliminary Diagnostic Table............................................................................................................................ 311

Test Descriptions............................................................................................................................................ 311

Diagnostic Table............................................................................................................................................. 312

Main Diagnostic Table....................................................................................................................................... 313

Test Descriptions............................................................................................................................................ 313

Diagnostic Table Notes .................................................................................................................................. 313

Diagnostic Table............................................................................................................................................. 313

5.26 Hazard Lamp Control......................................................................................................................................... 315

Circuit Description............................................................................................................................................. 315

Preliminary Diagnostic Table............................................................................................................................ 315

Test Descriptions............................................................................................................................................ 315

Diagnostic Table............................................................................................................................................. 315

Main Diagnostic Table....................................................................................................................................... 316

Test Descriptions............................................................................................................................................ 316

Diagnostic Table Notes .................................................................................................................................. 316

Diagnostic Table............................................................................................................................................. 316

Body Control Module Page 12J–13

Page 12J–13

6 Service Operations.............................................................................................................................318

6.1 Body Control Module......................................................................................................................................... 318

Mounting Location............................................................................................................................................. 318

BCM Preliminary Information............................................................................................................................ 318

Remove............................................................................................................................................................... 319

Access to BCM Without Disconnection.......................................................................................................... 319

Removal......................................................................................................................................................... 319

Reinstall.............................................................................................................................................................. 320

Original BCM.................................................................................................................................................. 320

Replacement BCM (New)............................................................................................................................... 320

BCM Relearn Procedure.................................................................................................................................... 320

6.2 Remote Coded Key............................................................................................................................................ 321

Key Replacement............................................................................................................................................... 321

6.3 Power Window A and B Door Pillar Wiring Loom Connectors...................................................................... 322

A Pillar X500 and X600 Connectors.................................................................................................................. 322

Remove.......................................................................................................................................................... 322

Reinstall ......................................................................................................................................................... 322

B Pillar X700 and X800 Connectors.................................................................................................................. 323

Remove.......................................................................................................................................................... 323

Reinstall ......................................................................................................................................................... 323

6.4 Bulb Re-learn Procedure Rear Lamp Warning Failure System...................................................................... 324

7 Torque Wrench Specifications .........................................................................................................325

8 Special Tools ......................................................................................................................................326

Body Control Module Page 12J–14

Page 12J–14

1 General Information

1.1 Abbreviations

The following abbreviations are used in this Section:

ABD Automatic Brake Differential

ABS Anti-lock Brakes

BCM Body Control Module

CTS Cooling Temperature Sensor

DLC Data Link Connector

ECM Engine Control Module

EBD Electronic Brake Distribution

EBL Electronic Boot Release

ECC Electronic Cruise Control

ESP Electronic Stability Program

ETC Electronic Throttle Control

FRPA Front and Rear Park Assist

HVAC Heating, Ventilation and Air Conditioning

GMLAN General Motors Local Area Network

INS Instrument Cluster

MFD Multi-function Display

MIW Message Identifier Word

OCC Occupant Climate Control

OPS Occupant Protection System

PCM Powertrain Control Module

PIM Powertrain Interface Module

PWM Pulse Width Modulation

RF Radio Frequency

RPA Rear Park Assist

SDIL Soft Dimming Interior Lights

SDM Sensing Diagnostic Module

TCM Transmission Control Module

TCS Traction Control System

TPM Tyre Pressure Monitor

UART Universal Asynchronous Receiver and Transmitter

VDC Vehicle Dynamic Control

VSS Vehicle Speed Sensor

Body Control Module Page 12J–15

Page 12J–15

1.2 Body Control Module

The body control module (BCM) controls various vehicle

electrical systems or features from one central module,

instead of using individual modules for each system or

feature.

The BCM is located beneath the instrument cluster to

the right of the steering column. The BCM is mounted

vertically, refer to Figure 12J – 98.

The BCM fitted to the various levels of vehicle is

physically the same, but with different functions enabled

via the BCM software.

Figure 12J – 1

Disconnect and remove all vehicle modules (after

disconnecting the battery) before performing any

welding, anywhere on the vehicle. Refer to

Section 00 Warnings Cautions and Notes. Failing

to do this can cause permanent damage to the

modules.

Body Control Module Page 12J–16

Page 12J–16

1.3 Body Control Module Models

Vehicle

Levels Vehicle

Models BCM

Levels

1 Ute

Reg Cab Low

1 Executive

Acclaim SV6 / SV8

S, SS

Crewman (All)

Mid

2 Berlina Lux

3 Calais

Monaro CV8 Lux

1 Adventra SX Mid

2 Adventra CX / LX Lux

Body Control Module Page 12J–17

Page 12J–17

1.4 Body Control Module Features

NOTE

Each model BCM includes a pre-delivery mode,

which sets the battery saver timer to a shorter

period of 3 minutes until the vehicle has travelled

above 20 km/h for a cumulative period of

30 minutes. After this period, the battery saver

timer sets to 1 hour.

The following list provides a summary of the features available on all level BCM’s.

• Remote deadlocking via remote key, two LOCK switch presses within 10 seconds.

• Battery saver feature; turns off all internal lamps after 1 hour (default setting) of the ignition being switched off.

• Key off courtesy lamp; courtesy lamp comes on for 30 seconds when the ignition is switched off.

• Disablement of the in-vehicle rear compartment release switch when the security system is armed.

• Approach illumination entry, headlamps and / or park lamps are turned on for 30 seconds (dependent on headlamp

switch position) when the vehicle is unlocked via the remote key.

Feature Table Key

Feature available 9

Feature not available X

Feature selectable by user U

Feature Table

Feature Function Description

Low

Mid

Lux

High

agon

Accessory power control

(delay accessories bus) Power to the audio system, windscreen

wiper and other accessories is removed

when the ignition is switched off.

9 9 9 9 9

Air conditioning interface system

(A/C switch) Momentary pressing of this switch

activates the air conditioning system.

NOTE

On Lux, High and AWD Wagon BCM’s,

this is controlled by the occupant climate

control module.

9 9 X X X

Airbag deployment vehicle shutdown Upon airbag deployment, the doors

unlock and the dome lamp illuminates for

10 seconds after the vehicle stops.

Engine and fuel pump turned off.

9 9 9 9 9

Approach

illumination Operates during darkened

conditions. The headlamps illuminate for 30 seconds

when the remote key unlocks the doors in

low light conditions.

9 9 9 9 9

Automatic

door-locking Selectable from instrument

cluster menu. All doors lock automatically when the

gearshift lever is moved out of the Park

position.

U U U U U

Automatic

lights off Turns off exterior lights

after a set period. With the park lamps, headlamps or auto

lamps on, the selected lamps remain on

after key off and the drivers door open for

a user adjustable period before switching

off automatically.

9 9 9 9 9

Body Control Module Page 12J–18

Page 12J–18

Feature Function Description

Low

Mid

Lux

High

agon

Automatic

lights on Turns lights on and off

automatically. The sun sensor automatically determines

when to turn on or off the headlamps

according to light conditions The wiper

switch position can force the lights to

come on earlier than normal.

9 9 9 9 9

Reduced standing current. After the vehicle has entered Battery

Saver mode, the battery current reduces

to less than 30 mA. The time to invoke

this mode is 10 seconds after remote

lock, key lock via driver’s door or 1 hour

after the ignition has been switched off.

9 9 9 9 9

Battery saver

Pre-delivery 3-minute

cutout. This mode exists on the vehicle until it

has travelled a total of 30 minutes at

speeds above 20 km/h.

9 9 9 9 9

Central

locking –

keyless entry

• Selectable whether

remote entry

operates driver only

or both doors.

• Engages door

deadlocks when

LOCK key button is

pressed twice.

• Releases both door

deadlocks when

unlocking vehicle.

• Operates exterior

lamps to show

location of car at

night.

• Enables or disables

the alarm system.

• Remote rear

compartment lid

release in glove box

disabled when

vehicle is locked.

• Applies a rolling

security code for

increased security.

• Horn chirps if either

door is ajar when

remote locking is

initiated.

Pressing the LOCK / UNLOCK key button

down will lock / unlock all doors

simultaneously.

Separate driver’s door only unlock, called

“2 stage unlock” is selectable from the

instrument cluster menu. If single stage

unlock is selected all door will unlock

when UNLOCK button is pressed.

A second press of the LOCK button

within the required time activates each

door deadlock.

9 9 9 9 9

Central locking – remote rear compartment

release. A separate button on the key releases the

rear compartment. X 9 9 9 9

Dome and

courtesy

lamp control

Entry delay, central locking

and ignition off courtesy

illumination.

The dome lamp is switched on from

various sources. Lamp shut-off timing is

triggered by ignition key switch off and

the driver’s door being opened and

closed.

9 9 9 9 9

Body Control Module Page 12J–19

Page 12J–19

Feature Function Description

Low

Mid

Lux

High

agon

Entry

deterrent

system

Vehicle immobilisation and

entry alarm. A range of security features provides the

highest level of security to the vehicle.

NOTE

No audible horn alarm fitted to level 1

vehicles.

9 9 9 9 9

Heated rear

window Control with delay. A timed 15 minute heating period

commences once this switch is activated.

NOTE

On Lux, High and AWD Wagon BCM’s,

this is controlled by the occupant climate

control module.

9 9 X X X

Instrument dimming control Holding the dimming switch on the

headlamp switch assembly in either the

Increase or Decrease position changes

instrumentation illumination.

9 9 9 9 9

Intermittent

wiper control Road speed dependent

variable dwell options. The intermittent wiper dwell time reduces

as the vehicle speed increases. X X U U U

Power

window

system

• Controls the vehicles

power windows

automatic functions.

• With driver and

passenger express

down.

• Windows remain

operative for a short

period after ignition is

switched off.

The express down feature operates when

the power window switches are held

down for more than 0.4 second.

X 9 9 9 9

Power

antenna

control

With height adjustment and

height memory. The radio antenna is height and drive

direction is controlled by the BCM when it

receives a radio request signal. The

height can be set and stored for Priority 1

and 2 keys.

X X 9 9 9

Body Control Module Page 12J–20

Page 12J–20

Feature Function Description

Low

Mid

Lux

High

agon

Priority key

automatically

applies

personalised

vehicle

settings for

two people

The BCM stores individual

settings for the following:

• Climate control,

• Sound system,

• Trip computer,

• Over speed alert,

• Transmission power–

economy mode,

• Instrument dimmer

level,

• Headlamps off time

delay,

• Accessories

shutdown control via

driver’s door opening

or ignition off,

• Dome lamp and

courtesy lamp timers,

• Single stage and two

stage unlock,

• Horn chirp when

LOCK and UNLOCK

button press,

• Speed dependant

wipers,

• Automatic lights on

setting (Early, Normal

and Late), and

• Memory seats.

Putting either Key 1 or 2 in the ignition

switch selects the choices made in the

systems listed.

X X 9 9 9

With speed interlock. The rear compartment cannot be

released at speeds over 20 km/h. X 9 9 9 NA Rear

compartment

release Disabled when armed. Rear compartment lid opening (by

pressing the switch in the glove box) is

disabled when the theft deterrent system

is armed, using the remote coded key

and doors locked via door lock barrel.

X 9 9 9 NA

Serial data interface The vehicle contains control modules that

communicate via a serial data system.

This permits Tech 2 interaction to enable

high-level diagnostic fault analysis.

9 9 9 9 9

Theft deterrent Engine is disabled to immobilise vehicle

when the key is removed from the

ignition. This will occur 30 seconds after

ignition off and is indicated by the theft

deterrent LED on the instrument cluster

flashing.

9 9 9 9 9

Body Control Module Page 12J–21

Page 12J–21

2 System Operation

2.1 Body Control Module Operating Modes

Battery Saver Mode

The BCM battery saver mode provides vehicle battery protection through reduced current consumption. After a preset

delay period controlled by the BCM’s internal shut down timer, the BCM:

• De-energises the interior illumination relay, which supplies battery voltage to all interior lamps including the dome

lamp, ignition lock, instrument panel compartment and rear compartment lamps. This protects the battery when:

• A lamp is mistakenly left on because a door is left open, or

• A faulty illumination circuit or component is causing excess current consumption.

• De-energises the power window relay. This action is separate from the normal Power Window Off Delay function.

• Disables the BCM inputs normally not required when the ignition is off.

• De-energises the accessories relay.

The battery saver delay period has a default value of 60 minutes, however it can be set from 3 – 180 minutes using

Tech 2. The delay period starts when the ignition is switched off.

If the BCM is in battery saver mode, all the BCM inputs are re-enabled when:

• The hood, rear compartment lid or any door is opened,

• The BCM receives a valid RF key lock, unlock or rear compartment signal from the remote coded key,

• The ignition switch is turned on or to the accessories position,

• The doors are unlocked via the driver’s door micro switch,

• The deadlock switch is operated,

• Tech 2 is communicating with the BCM,

• The headlamp switch is cycled from off to on or from on to off,

• The rear compartment release switch, located in the glove box, is operated,

• The alarm is activated (if fitted),

• Hazard switch on, or

• Accessories on via radio trigger.

Pre-delivery Mode

To provide additional battery protection the vehicle is delivered with the BCM in pre-delivery mode. In this mode, the

battery saver period is set to 3 minutes.

Pre-delivery mode is disabled once the vehicle has travelled for a total of 30 minutes at speeds above 20 km/h. This

value is estimated to be the equivalent period prior to customer delivery.

Pre-delivery mode may also be enabled and disabled using Tech 2.

Body Control Module Page 12J–22

Page 12J–22

2.2 Serial Data Communication – V6

System Overview

Vehicles that are fitted with a HFV6 engine use GM LAN (General Motors Local Area Network) serial data

communications system for powertrain components. The modules use GM LAN communications to transfer information

between each other and bi directionally to the powertrain interface module (PIM). GM LAN has a major advantage over

the former Class 2 system of data communication in that it transfers data much faster.

Refer to the system block diagram Figure 12J – 2 showing how the control modules within the vehicle are connected to

the BCM via the GM LAN and UART (Bus Master) systems.

Body Control Module Page 12J–23

Page 12J–23

V6 Serial Data Block Diagram

NOTE

Serial data components shown in the block

diagram will vary depending on vehicle options.

Figure 12J – 2

Legend

1 Body Control Module (BCM)

2 Powertrain Interface Module (PIM)

3 Steering Angle Sensor (SAS)

4 ABS-TCS / ESP Electronic Control Unit

5 Engine Control Module (ECM)

6 Transmission Control Module (TCM)

7 Audio Head Unit (AHU)

8 Memory Seat Module (MSM)

9 Instrument Cluster

10 Occupant Protection System Sensing and Diagnostic

Module (SDM)

11 Data Link Connector

12 Tech 2 Diagnostic Tool

A GM LAN serial data circuit

B Primary UART serial data circuit

C Secondary UART serial data circuit

D Tertiary UART serial data circuit

Body Control Module Page 12J–24

Page 12J–24

The GM LAN Bus System

The term GM LAN means the various engine and vehicle control modules are linked together on a common twisted pair

bi directional data bus.

The advantages of using GM LAN are:

• Fewer sensors and signal wires are necessary due to the multiple uses of common sensor signals.

• Fewer wires are needed in the cable harnesses.

• Smaller wiring harnesses results in an overall vehicle weight reduction.

• Fewer plug-in terminals are required in the control unit connectors.

• Improved reliability and serviceability is achieved.

The GM LAN bus system communicates between the ECM, TCM, ABS / TCS and PIM via a dual wire network, which is a

high-speed differential bus with a transmission speed of 500K bits / second. It is designed as a dual wire system

comprising one tan / black wire (CAN-High) and another tan wire (CAN-Low). The wires are twisted together to prevent

electro-magnetic interference being caused to other control units within the vehicle. The twisting of these wires eliminates

any magnetic fields that are created by the rapid voltage changes on the lines.

GM LAN module’s have various vehicle peripheral devices such as sensors and switches connected to them. The

module either reads data from these peripheral devices, or sends commands to them. The timing as to when data is read

from or sent to it is most often determined by either engine or vehicle operating conditions, which is received from other

control modules connected to the GM LAN.

Data transmitted from any module is sent to all GM LAN control modules connected to the bus. Each control module has

to assess whether the data it receives is required for it to process and if necessary, to act upon it.

UART Communications

Tech 2 and the vehicle system body control modules communicate with and between each other using serial data. Serial

data transfers information, one bit at a time, over a single line called the UART data bus.

The UART bus is a 5-volt data line that toggles the voltage to ground (0 V) at a fixed bit pulse-width during

communication and transmits data at the frequency of 8.2 kilobits per second (8192 bits/second) to all modules

connected to it. When there is no communication on the data line, the system voltage remains constant at 5 V.

Serial Data Bus

The serial data bus is divided into three sections, these being:

• Primary data bus.

The BCM uses the primary data bus, circuit 800, for communication with the Powertrain Interface Module (PIM) A5.

• Secondary data bus.

The BCM uses the secondary data bus, circuit 1061 for communication with the remaining modules, except the

OPS / SDM module A65.

• Tertiary data bus.

The BCM uses the tertiary data bus, circuit 774, for communication with the Occupant Protection System OPS /

SDM A65.

Body Control Module Page 12J–25

Page 12J–25

Data Bus Device Polling

The BCM periodically polls (surveys) each device on the Primary, Secondary and Tertiary data buses, which includes the

BCM itself, and requests each module’s status data. The following devices and control modules are polled:

Primary Serial Data Bus

• PIM (A5).

• Tech 2 diagnostic scan tool.

Secondary Serial Data Bus

• instrument cluster (P3).

• audio head unit (A133)

• memory seat module (A21)

• HVAC (A14)

Tertiary Serial Data Bus

• Occupant protection system (OPS) and sensing and diagnostic module (SDM) A65.

The BCM polls each of the above listed devices for a status update every 300 milliseconds with the exception of the PIM

and radio, which are polled twice every 300 milliseconds. An internal, software controlled switch (within the BCM) can

isolate the secondary data bus and the tertiary data bus from the primary data bus if a short circuit appears on either the

secondary or tertiary data buses. When this switch is opened by the BCM, this permits the vehicle to start and run for

short distances with limited facilities available to the driver such as instrumentation, radio, etc.

Tech 2 and the Data Link Connector

The DLC provides an interface between Tech 2 and the two data bus systems. The X40 Data Link Connector (DLC)

provides the facility for Tech 2 to communicate to the vehicle’s control modules via the GM LAN and Bus Master UART

systems.

Tech 2 communicates with the ECM and other powertrain control modules via its own direct connection to the GM LAN

via the DLC. It also communicates with the BCM via the DLC’s Primary UART Bus.

Inputs and Outputs

To aid in the following description, refer to 3 Wiring Diagrams and Connector Charts.

GM LAN Data Bus

The GM LAN twisted pair data bus is connected to CAN_LO and CAN_HI between the PIM and the ECU, ABS / TCS,

TCM and the SAS control modules. The GM LAN data bus is also available at the data link connector (DLC)

Serial Data Signal – Primary UART

The BCM primary serial data bus A15 – X2 pin 5 is connected to the PIM A5 – X1 pin 10 and the data link connector

(DLC) to Tech 2 via circuit 800. It is through the Primary UART Bus the BCM communicates with the PIM and with

Tech 2 when it is connected to the DLC.

Serial Data Signals – Secondary and Tertiary UART

The BCM secondary serial data bus A15 – X2 pin 9 is connected to the instrument cluster (P3), the audio head

unit (A133), the memory seat module (A21) and the HVAC module (A14) via circuit 1061.

The BCM tertiary serial data bus A15 – X2 pin 6 is connected to the OPS / SDM module (A65) via circuit 774. It is

through circuits 1061 and 774 the BCM communicates with these devices after successful theft deterrent

communications has occurred between the PIM and BCM.

The secondary and tertiary serial data buses are isolated from the primary serial data bus within the BCM if the BCM

does not receive an OK To Start message from the PIM within 0.5 second of the ignition being switched to the ON

position. If there is still no acknowledgment from the PIM after this time, this isolation continues for a 5 second period

before the BCM re-commences polling.

Body Control Module Page 12J–26

Page 12J–26

Data Bus Device Polling

The BCM controls all modules on the UART serial data communication system. The BCM periodically polls (surveys)

each device on the data bus, including the BCM itself, and requests status data. The following devices and control

modules are polled:

• powertrain interface module (PIM),

• instrument cluster,

• occupant protection system (OPS) sensing and diagnostic module (SDM),

• blower motor and A/C compressor module (HVAC),

• audio system head unit (AHU),

• memory seat module (MSM),

• Tech 2 diagnostic scan tool, and

• the BCM itself.

The BCM polls each device for a status update every 300 milliseconds, with the exception of the PIM and radio which are

polled twice every 300 milliseconds.

Data Messages

Any device connected to the bus can use the data provided by each device.

Each device has a unique response message identifier word (MIW) for ease of identification. The BCM polls each device

with a serial data message that includes the device MIW. The device responds with a serial data message including its

MIW with the data, which is retrieved and used by any device requiring it.

Powertrain Interface Module

The powertrain interface module (PIM) is the hardware and serial communications interface between the engine ECM

and powertrain, braking, traction control and steering control modules that are connected to the GM LAN data bus. The

PIM acts as a transparent bi-directional translation device that allows data to flow between the above modules on the

GM LAN data bus and converts this data to UART serial data protocols for the BCM to process and act on.

Refer to Section 6E1 Powertrain Interface Module – V6 for further detailed information.

Body Control Module Page 12J–27

Page 12J–27

2.3 Serial Data Communication – GEN III V8

System Overview

GEN III V8 vehicles use both the UART bus master system to communicate between the BCM and various body modules

and Class 2 communications to communicate between the powertrain interface module (PIM) and the powertrain control

module (PCM).

Class 2 uses a different communications language to UART, therefore direct communication between the modules is

incompatible and requires an interface module PIM to convert Class 2 communication into UART and UART into Class 2.

Refer to Section 6E3 Powertrain Interface Module GEN III V8 for further details.

Refer to the system block diagram Figure 12J – 3 showing how the control modules within the vehicle are connected to

the BCM via the Class 2 and UART (Bus Master) system.

Body Control Module Page 12J–28

Page 12J–28

GEN III V8 Serial Data Block Diagram

NOTE

Serial Data Components shown in the block

diagram will vary depending on vehicle options.

Figure 12J – 3

Legend

1 Body Control Module (BCM)

2 Powertrain Interface Module (PIM)

3 Powertrain Control Module (PCM)

4 Audio Head Unit (AHU)

5 Memory Seat Module (MSM)

6 Instrument Cluster

7 Antilock Brake System (ABS)

8 Occupant Protection System Sensing and Diagnostic Module (SDM)

9 Data Link Connector

10 Tech 2 Diagnostic Tool

A Class 2 data circuit

B Primary UART serial data circuit

C Secondary UART serial data circuit

D Tertiary UART serial data circuit

Body Control Module Page 12J–29

Page 12J–29

UART and Class 2 Serial Data Bus

Tech 2 and the vehicle system control modules communicate with and between each other using serial data. Serial data

transfers information, one bit at a time, over a single line called the universal asynchronous receive and transmit UART

data bus. UART is a communications protocol that has a master module, which controls the message traffic on the serial

data bus. The body control module is the UART bus master.

The UART bus is a 5-volt data line that toggles the voltage to ground (0 V) at a fixed bit pulse-width during

communication and transmits data at the frequency of 8.2 kilobits per second (8192 bits/second) to all modules

connected to it. When there is no communication on the data line, the system voltage remains constant at 5 V.

The PIM communicates with the PCM using Class 2 data communications. This type of communications toggles the data

line from 0 V to 7 V with either a short or long pulse width at an average frequency of 10.4 kilobits per second. In Class 2

communications, where there is no communications on the data line, the system voltage is 0 V. Class 2 communication

protocol enables communications directly between the modules on the bus without the need for a bus master.

The serial data bus is divided into three sections, these being:

• Primary data bus.

The BCM uses the primary data bus, circuit 800, for communication with the powertrain interface module PIM A5.

• Secondary data bus.

The BCM uses the secondary data bus, circuit 1061 for communication with the remaining modules, except the

OPS / SDM module A65.

• Tertiary data bus.

The BCM uses the tertiary data bus, circuit 774, for communication with the occupant protection system OPS /

SDM A65.

Data Bus Device Polling

The BCM periodically polls (surveys) each device on the primary, secondary and tertiary data buses, which includes the

BCM itself, and requests each module’s status data. The following devices and control modules are polled:

Primary Serial Data Bus

• PIM (A5).

• Tech 2 diagnostic scan tool.

Secondary Serial Data Bus

• instrument cluster (P3).

• audio head unit (A133)

• memory seat module (A21)

• HVAC (A14)

Tertiary Serial Data Bus

• occupant protection system (OPS) and sensing and diagnostic module (SDM) A65.

The BCM polls each of the above listed devices for a status update every 300 milliseconds with the exception of the PIM

and radio, which are polled twice every 300 milliseconds. An internal, software controlled switch (within the BCM) can

isolate the secondary data bus and the tertiary data bus from the primary data bus if a short circuit appears on either the

secondary or tertiary data buses. When this switch is opened by the BCM, this permits the vehicle to start and run for

short distances with limited facilities available to the driver such as instrumentation, radio, etc.

Tech 2 and the Data Link Connector

The DLC provides an interface between Tech 2 and the two data bus systems. The X40 Data Link Connector (DLC)

provides the facility for Tech 2 to communicate to the vehicle’s control modules via the GM LAN and Bus Master

systems.

Tech 2 communicates with the BCM via the DLC’s primary UART bus as well as the receiving bi-directional Class 2 data

communications from the PIM and PCM. Tech 2 is able to communicate with both UART and Class 2 control modules.

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Inputs and Outputs

To aid in the following description, refer to 3 Wiring Diagrams and Connector Charts.

Class 2 Serial Data Signal

Class 2 serial data flows bi-directional between the PIM A5 – X1 pin 7 and the PCM A84 – X1 pin 58 and is also present

at the data link connector (DLC) to Tech 2 via circuit 1045.

Serial Data Signal – Primary UART

The BCM primary serial data bus A15 – X2 pin 5, is connected to the PIM A5 – X1 pin 6 and the data link connector

(DLC) to Tech 2 via circuit 800. It is through the primary UART Bus the BCM communicates with the PIM and with Tech 2

when it is connected to the DLC.

Serial Data Signal – Secondary and Tertiary UART

The BCM secondary serial data bus A15 – X2 pin 9, is connected to the instrument cluster (P3), the audio head

unit (A133), the memory seat module (A21) and the HVAC module (A14) via circuit 1061.

The BCM tertiary serial data bus A15 – X2 pin 6 is connected to the OPS / SDM module (A65) via circuit 774. It is

through circuits 1061 and 774 the BCM communicates with these devices after successful theft deterrent

communications has occurred between the PIM and BCM.

The secondary and tertiary serial data buses are isolated from the primary serial data bus within the BCM if the BCM

does not receive an OK To Start message from the PIM within 0.5 second of the ignition being switched to the ON

position. If there is still no acknowledgment from the PIM after this time, this isolation continues for a 5 second period

before the BCM re-commences polling.

Data Bus Device Polling

The BCM controls all modules on the UART serial data communication system. The BCM periodically polls (surveys)

each device on the data bus, including the BCM itself, and requests status data. The following devices and control

modules are polled:

• powertrain interface module (PIM),

• instrument cluster,

• antilock brake / traction control system (ABS/TCS) module,

• occupant protection system (OPS) sensing and diagnostic module (SDM),

• blower motor and A/C compressor module (HVAC),

• audio system head unit (AHU),

• memory seat module (MSM),

• Tech 2 diagnostic scan tool, and

• the BCM itself.

The BCM polls each device for a status update every 300 milliseconds, with the exception of the PIM and radio which are

polled twice every 300 milliseconds.

Data Messages

Any device connected to the bus can use the data provided by each device.

Each device has a unique response message identifier word (MIW) for ease of identification. The BCM polls each device

with a serial data message that includes the device MIW. The device responds with a serial data message including its

MIW with the data, which is retrieved and used by any device requiring it.

Powertrain Interface Module

The powertrain interface module (PIM) is the hardware and serial communications interface between the powertrain

control module (PCM) connected together via the Class 2 data bus. The PIM acts as a transparent bi-directional

translation device that allows data to flow between the PCM and converts this data to UART serial data protocols for the

BCM to process and act on.

Refer to Section 6E3 Powertrain Interface Module GEN III V8 for further detailed information.

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2.4 Serial Data Communication – GEN IV V8

System Overview

Vehicles that are fitted with a GEN IV V8 engine use GM LAN (General Motors Local Area Network) serial data

communications system for powertrain components. The modules use GM LAN communications to transfer information

between each other and bi directionally to the powertrain interface module (PIM). GM LAN has a major advantage over

the former Class 2 system of data communication in that it transfers data much faster.

Refer to the system block diagram Figure 12J – 4 showing how the control modules within the vehicle are connected to

the BCM via the GM LAN and UART (Bus Master) systems.

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GEN IV V8 Serial Data Block Diagram

NOTE

Serial data components shown in the block

diagram will vary depending on vehicle options.

Figure 12J – 4

Legend

1 Body Control Module (BCM)

2 Powertrain Interface Module (PIM)

3 Steering Angle Sensor (SAS)

4 ABS-TCS / ESP Electronic Control Unit

5 Engine Control Module (ECM)

6 Transmission Control Module (TCM)

7 Audio Head Unit (AHU)

8 Memory Seat Module (MSM)

9 Instrument Cluster

10 Occupant Protection System Sensing and Diagnostic

Module (SDM)

11 Data Link Connector

12 Tech 2 Diagnostic Tool

A GM LAN serial data circuit

B Primary UART serial data circuit

C Secondary UART serial data circuit

D Tertiary UART serial data circuit

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