SECTION 6C3-2 - DIAGNOSIS - GEN III V8 ENGINE
IMPORTANT:
Before performing any Service Operation or other procedure described in this Section, refer to 00
CAUTIONS AND NOTES in this VX Service Information for correct workshop practices with regards to
safety and/or property damage.
GENERAL DES CRIPTION
This is where to start all driveability and emissions diagnosis, once you read and understand
Section 6C3-1 GENERAL INFORMATION of the VX Series Service Information. The beginning of
Section 6C3-2A contains reference material: wiring diagrams, control module terminal end views, and engine
component locations. Remember, this information is for reference; do not start diagnosis using these pages. Always
start diagnosis on the page titled Powertrain OBD System Check . T his chec k verifies that the diagnostic circuits are
operating properly, then sends you to the correct Service Information for diagnosis.
If the initial steps in the Powertrain OBD System Check reveal a problem, or if the engine does not start, you will be
using one or more tables in Section 6C3-2A of the VX Series Service Information for diagnosis. The Powertrain
OBD System Check will send you to the cor rect table. These tables follow the Powertrain OBD Sys tem Check and
problems that prevent the engine from starting.
If the Powertrain OBD System Check shows that Diagnostic Trouble Codes have been stored, proceed to the
appropriate Diagnostic Trouble Code (DTC) diagnosis pages. If more than one Diagnostic Trouble Code has been
stored, always star t Diagnostic T rouble Code diagnos is with the lowest Diagnos tic Trouble Code num ber and work
upward. Diagnostic Trouble Code diagnosis pages start immediately after the diagnosis tables in Section 6C3-2A.
DIAGNOSTIC PRECAUTIONS
THE FOLLOWING REQUIREMENTS MUST BE OBSERVED WHEN WORKING ON VEHICLES.
1. Before removing any PCM system component, disconnect the battery earth lead.
2. Never start the engine without the battery being solidly connected.
3. Never separate the battery from the on board electrical system while the engine is running.
4. When charging the battery, disconnect the battery from the vehicle's electrical system.
5. Never subject the PCM to temperatures above 80° C i.e. paint oven. Always remove control unit first if this
temperature is to be exceeded.
6. Ensure that all cable harness plugs are connected solidly and that battery terminals are thoroughly clean.
7. The powertrain m anagem ent s ystem harnes s connec tors ar e designed to fit in only one way; there ar e indexing
tabs and slots on both halves of the connector. Forcing the connector into place is not necessary if it is being
installed with the proper orientation. Failure to take care to match the indexing tabs and slots to ensure the
connector is being installed correctly can cause damage to the connector, the module, or other vehicle
components or systems.
8. Never connect or disconnect the cable harness plug at the PCM when the ignition is switched ON.
9. Before attempting any electric Arc welding on the vehicle, disconnect the battery leads and the PCM
connectors.
10. When steam cleaning engines, do not direct the steam cleaning nozzle at PCM system components. If this
happens, corrosion of the terminals can take place.
11. Use only the test equipm ent specified in the diagnostic tables. Other test equipm ent may either give incorrect
results or damage good components.
12. All voltage m easurements using a voltmeter m ust use a digital multim eter with an internal impedance rating of
at least 10 million ohms per volt (10 mega ohms) such as the DMM J 39200.
13. When a test light is specified, a "low-power" test light must be used. Do not use a high - wattage test light. While
a particular brand of test light is not suggested, a simple test on any test light will ensure it to be OK for PCM
circuit testing. Connect an acc urate am meter ( such as the high- impedance digital m ultim eter) in ser ies with the
test light being tested, and power the test light/ammeter circuit with the vehicle battery.
Figure 6C3-2-1
If the ammeter indicates less than 3/10 amp current flow (0.3 A or 300 ma), the test light is OK to use.
If the ammeter indicates more than 3/10 amp current flow (0.3 A or 300 ma), the test light is NOT OK to use.
+
BATTERY
-
DC AMPS
TEST LIGHT
BLOCKING DRIVE WHEELS
The vehicle drive wheels always should be blocked and the parking brake firmly set while checking any system.
VISUAL/PHYSICAL INSPECTION
A car ef ul vis ual and physical ins pection mus t be per f ormed as part of any diagnostic procedure. This can often lead
to fixing a problem without further steps. Inspect all the wires in the engine compartment for bad connections,
burned or chafed spots, pinched wires, or contact with sharp edges or hot exhaust manifolds. Also, inspect all the
wires. Check beneath the air cleaner, the compressor, the generator, etc. This visual/physical inspection is very
important. The inspection must be done carefully and thoroughly.
BASIC KNOWLEDGE AND TOOLS REQUIRED
To Service Information Package most effectively, a general understanding of basic electrical circuits and circuit
testing tools is required. You should be familiar with wiring diagrams, the meaning of voltage, ohms, amps, the
basic theories of electricity, and understand what happens in an open or shorted circuit.
To perform system diagnosis, the following tools are required.
• A Tech 2 scan tool
• A test light
• A digital multimeter with 10 megaohms impedance
• A vacuum gauge
• A fuel pressure gauge and suitable fittings
• Fuel injector coil/ balance tester
• IAC motor analyser
Familiarise yourself with the tools and their uses before attempting diagnosis. Special tools that are required for
system service and the ones described above are illustrated in Section 6C3-6 SPECIAL TOOLS, at the end of this
Section.
ELECTROSTATIC DISCHARGE DAMAGE
Electronic components used to control the systems are often designed to carry very low voltage. They are very
susc eptible to dam age caused by electr ostatic discharge. It is possible for les s than 100 volts of static electricity to
cause damage to some electronic components.
By comparison, it takes as much as 4000 volts for a person to even feel the zap of a static discharge.
There are several ways for a person to become statically charged. The m ost common methods of charging are by
fric tion and by induction. An ex ample of charging by friction is a per son sliding acr oss a car seat, in which a char ge
of as much as 25 000 volts can build.
Charging by induction occurs when a person with well-insulated shoes stands near a highly charged object and
momentar ily touches earth. Char ges of the s ame polarity are drained off , leaving the per son highly charged with the
opposite polarity. Static charges of either type can cause damage, therefore, use care when handling and testing
the electronic components.
NOTE: To prevent possible Electrostatic Discharge damage:
Do Not touch the PCM connector pins or soldered components on the PCM circuit board.
DIAGNOSTIC INFORMATION
The diagnostic tables and functional checks of the VX
Series Service Information are designed to locate a
faulty circuit or component through logic based on the
process of elim ination. T he tables are prepared with the
understanding that the vehicle:
• Functioned correctly at the time of assembly.
• There are no multiple faults.
• The problem currently exists.
The PCM/PIM performs a continual self-diagnosis on
certain control functions. This diagnostic capability is
supported by the diagnostic procedures. The PCM/PIM
indicates the source of a fault through the use of
Diagnostic Trouble Codes (DTCs). The DTCs are four
digit (PCM will be P0XXX or P1XXX and PIM will be
B2XXX). When a fault is detected by the PCM/PIM, a
Diagnostic Trouble Code will set and the Check
Powertrain Lamp (CPL) may illuminate.
SELF DIAGNOSTICS
The PCM/PIM performs system self diagnostics. The
PCM/PIM can detect and often isolate system faults.
W hen a fault is detected, the PCM/PIM sets a DTC that
represents the area of the fault. The PCM/PIM may, or
may not, turn ON the Check Powertrain Lamp (CPL).
CHECK POWERTRAIN LAMP (CPL)
The instruments receive Check Powertrain Lamp
(CPL) information from the PCM via the serial data
bus normal mode message.
The PCM will command the instruments to turn on
the Check Power train Lamp (CPL) for two seconds
when the ignition is first tur ned on and when a DTC
has been set and the DTC requires the lamp to be
illuminated.
If the instruments do not receive a normal mode
me ss age f r om the PCM, the CPL will be illuminated
continuously. When the Check Powertrain Lamp
(CPL) remains ON while the engine is running, or
when a fault is suspected due to a driveability or
emissions problem, perform the "On-Board
Diagnostic System Check". Refer to
POWERTRAIN OBD SYSTEM CHECK in Section
6C3-2A of the VX Series Service Information.
Thes e c hecks will help identif y faults which may not
be detected if other diagnostics are performed.
Figure 6C3-2-2 Check Powertrain Lamp (CPL)
INTERMITTENT CHECK POWERTRAIN LAMP (CPL)
In the case of an "intermittent" problem, the Check
Powertrain Lamp (CPL) may light for ten seconds
and then go out. The corresponding Diagnostic
Trouble Code will be stored. The DTC will remain
stored until the battery voltage to the PCM has
been disconnected or until it is erased using the
Tech 2 scan tool. When unexpected diagnostic
trouble codes appear, chances are that these
diagnostic trouble c odes were set by an interm ittent
fault.
An intermittent DTC may not re-set. If an
intermittent fault occurs, do not use a Diagnostic
Trouble Code Table. Consult the "Diagnostic Aids"
on the facing page. The diagnostic table
corresponds to the intermittent diagnostic trouble
code.
SYMPTOMS TABLES, Section 6C3-2B of the VX
Series Service Information also covers the topic of
"Intermittents." A physical inspection of the
applicable sub-system most often will resolve the
problem. The Tech 2 scan tool also has several
features which can help in diagnosing intermittent
problems.
Figure 6C3-2-3 Check Powertrain Lamp Circuit
G3PCM036PT
M
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O
M
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INSTRUMENTBCM
12 SERIAL
DATA
5V
CHECK
POWERTRAIN
LAMP
12V
G/W (1220)
YB66
YB175
YB164
YB215 YE122
J1-58
M
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O
CLASS 2
SERIAL DATA
PCM
7V
R/B (1221)
PIM
UART
SERIAL
DATA
5V
6
Y (1049)
7V
7
CLASS 2
SERIAL DATA
M
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R
O
E2/D2
E9/D3
SERIAL
DATA
MAIN
SERIAL
DATA AUX.
HIGH SERIES
BCM TERMINALS
NOMINATED FIRST
5V
DATA LINK CONNECTOR
The DLC is a standardised 16 way connector
located below the instruments panel and close to
the steering column.
1
3
2
Figure 6C3-2-4 Data Link Connector (DLC)
LocationSteering Column Lower Cover
2. Data Link Connector
3. Instrument Panel Right Hand Cover Assembly
The DLC pin 1 is the Secondary UART serial data
circuit.
Tech 2 does not communicate with anything on
terminal 1 this is only used for engineering
purposes.
Pin 4 is the earth circuit for Tech 2, Pin 5 is an
auxiliary earth, that should be used to earth the
Diagnostic Test Enable Circuits.
The DLC pin 6 is the PCM Diagnostic Test Enable
circuit. T his circ uit when jumper ed to DLC pin 5 will
cause the PCM enter the Diagnostic Mode. The
PCM Diagnostic Mode is described later in this
section.
The DLC pin 9 is the primary UART serial data
circuit. The Tech 2 scan tool uses this circuit to
read serial data information from the PCM and
BCM, Instruments, Electronic Climate Control, and
the ABS/ETC Control Modules.
The DLC pin 12 is the ABS/ETC Diagnostic Test
Enable circuit. This circuit when jumpered to DLC
pin 5 will cause the ABS/ETC Control Module to
enter the Diagnostic Mode and flash out ABS/ECT
trouble codes.
The DLC is designed to provide battery voltage to
pin 16 from fuse F31. This circuit is used to power
the Tech 2 scan tool.
1
9
2
10
3
11
4
12
5
13
6
14
7
15
8
16
Figure 6C3-2-5 Data Link Connector (DLC)
1. Secondary Serial Data (UART)
2. Serial Data (Class II)
4. Earth
5. Earth
6. Diagnostic Test Enable
9. Primary Serial Data (UART)
12. ABS Diagnostic Test Enable
16. Battery Voltage
Figure 6C3-2-6 Data Link Connector Circuits
G3PCM057APT
PCM
J1-58 CLASS 2
SERIAL
DATA
7V
BCM
E2/D2
E9/D3
E3/D13
M
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O
SERIAL
DATA
MAIN
SERIAL
DATA AUX.
5V
W/G (1220)
Y/R (88)
G/W (1220)
HIGH SERIES
BCM TERMINALS
NOMINATED FIRST
DATA LINK
CONNECTOR
12345678
910111213141516
Y (1049)
LOC. E3
B/Y (155)
B (150)
INSTRUMENTS
ABS/ETC
11
SERIAL
DATA
5V
12 SERIAL
DATA
5V
M
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CHECK
POWERTRAIN
OIL PRESSURE
POWER ECONOMY
LOW COOLANT
R
12V
P
N
D
3
1
2
SRS
ECC
9
6
M
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M
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SERIAL
DATA
SERIAL
DATA
5V
12V IGN
17
12V
VEHICLE
SPEED
18
12V
TACHO
SIGNAL
SPEEDOMETER
TACHO
TACHO
SIGNAL
VEHICLE
SPEED
J2-10
J2-50
V/W (123)
BR/R (121)BR (121)
M
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P
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S
S
O
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LOW TR ACTI ON 20
BRAKE SWITCH
J1-33
BR (8 6)
PIM
M
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R/B (1221)
UART
SERIAL
DATA
5V
6
12V
11
DI AG. ENABL E
Y (1049)
7V
7
CLASS 2
SERIAL DATA
W/B (451)
STOP LAMP
SWITCH B
(NC)
M
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11 LOW
TRACTION
LAMP
YE122
YE123
YB12
YB12
YB66
YB191
YB190
YB189
YE98
YB87
YB175
YB164
YB215
STRATEGY BASED DIAGNOSTICS
The s tr ategy based diagnos tic is a unifor m approac h to repair all Elec tric al/Elec tr onic ( E/E) system s . The diagnostic
flow can always be used to resolve an E/E s ystem problem and is a star ting point when repairs are necessary. T he
steps below are def ined to instruct the tec hnician how to proceed with a diagnostic proces s. Steps below also ref er
to step numbers found on the Strategy Based Diagnostic table.
1. Verify the Driver Concern: To verify the driver concern, the technician should know the normal operation of
the system.
2. Preliminary Check: Conduct a thorough visual and operational inspection. Review the service history, detect
unusual sounds or odours, and gather Diagnostic Trouble Code information to achieve effective repair.
3. Service information (Manual) System Check(s): System checks verify proper operation of the system. This
will lead the technician in an organised approach to diagnostics.
4. Check Bullet ins and Other Serv ice Information: T his should include videos, newsletters , and service centre
updates.
5. Service Diagnostics (Paper/Electronic)
5.1 DTC Stored: Follow the designed DTC table exactly to make an effective repair.
5.2 Symptom, No DTC: Select the symptom from the symptom tables and follow the diagnostic paths or
suggestions to complete the repair, or ref er to the applicable component/system checks in Section 6C3-2C of
the VX Series Service Information.
5.3 No Published Diagnostics: Analyze the complaint and develop a plan for diagnostics. Utilise the wiring
diagrams and theory of operation.
Call technical assistance for similar cases where repair history may be available. Combine technician
knowledge with efficient use of the available service information.
5.4 Intermittent faults: Conditions that are not always present are intermittent. To resolve intermittents,
perform the following steps:
5.4.1 Observe history DTCs, DTC modes and Freeze Frame data.
5.4.2 Evaluate the symptoms and conditions described by the driver.
5.4.3 Use a check sheet or other method to identify the circuit or electrical system component.
5.4.4 Follow the suggestions for intermittent diagnosis found in the service documentation.
The Tech 2 and DMM have data capturing capabilities that can assist in detection of intermittents.
5.5 Vehicle Operates As Designed/No Trouble Found: This condition exist when the vehicle is found to
operating normally. The condition descr ibed by the driver m ay be normal. Ver if y against another vehicle that
is operating normally. The condition may be intermittent. Contact Technical Assistance if the concern is
common. Verify the complaint under the conditions described by the driver before releasing the vehicle.
6. Re-examine the Concern: When the complaint cannot be successfully found or isolated, a reevaluation is
necessary. The complaint should be re-verified and could be intermittent or normal as per step 5.3 or 5.5.
7. Repair and Verification T ests: Af ter isolating the cause, the repair s hould be made. T hen validate for proper
operation and verify that the symptom has been corrected. This may involve road testing or other methods to
verify the complaint has been resolved under the following conditions:
• Conditions noted by the driver.
• If a DTC was diagnosed, verify a repair by duplicating conditions present when a DTC was set as noted in
the Freeze Frame/Failure Records data.
Figure 6C3-2-7 Strategy Based Diagnostics
STRATEGY BASED DIAGNOSTICS
VERIFY DRIVER CONCERN
PRELIMI NARY CHECKS
Visual and Operational
Perform Published
POWERTRAI N OBD SYSTEM CHECK
CHECK FOR BULLETINS
(Printed/DCS/Techline Equipment)
1
2
3
4
STORED SYMPTOM
DTC(S) NO DTC(S)
FOLLOW FOLLOW
PUBLISHED PUBLISHED
DTC SYMPTOM
DIAGNOSTICS DIAGNOSTICS
NO PUBLISHED INTERMITTENT
DIA GNOSTICS
Analyze & Develop SEE
Diagnostics or Call DIAGNOSTIC
Technical DETAILS
Assistance
5.1 5.2 5.3 5.4
OPERATING AS DESIGNED
• Driver Misunderstanding of System:
Refer to Management or Zone
• P roduct Problem: Call Technical
Assistance
ISOLATE THE PROBLEM
REPAIR & VERI F Y FI X
RE-EXA MINE
THE CONCERN
5.5
NO
YES
7
6
DIAGNOSTIC TROUBLE CODES
DTCs are stored with various additional information:
• History: fault has been detected by the control module but might not be set at the moment.
• CPL or Message Requested: Check Powertrain Malfunction Indicator Lamp has been turned ON.
• Last Test Failed.
• Test Failed Since Code Cleared.
• Not Ran Since Code Cleared: controller has not tested yet if fault is active.
• Failed This Ignition.
HOW TO USE THE FREEZE FRAME / FAILURE RECORDS INFORMA TION
When a PCM DTC is set, there will be a Freeze Frame/Failure Record for that DTC. The Freeze Frame/ Failure
Records data list has 32 parameters for data capture. When a DTC is set, the control module will capture all 32
parameters at the time the DTC is logged. When a technician is diagnosing a DTC, this Freeze Frame/Failure
Record information can be retrieved and reviewed to assist in diagnosis.
In addition to the regular data list parameters found in the Freeze Frame/Failure Records data list, there is
additional information available about the DTC diagnostics:
• FIRST ODOMETER - vehicle kilometre value when the DTC failure first recorded
• LAST ODOMETER - vehicle kilometere value when the DTC fail is recorded
• FAIL COUNTER - number of ignition cycles wi th failure (DTC was set)
• PASS COUNTER - number of ignition cycles with diagnostic passes (DTC was not set again)
• NOT RUN COUNTER - number of ignition cycles without diagnostic run (DTC conditions were not tested)
READING THE DTCS
The provision for communicating with the PCM/PIM is the Data Link Connector (DLC). The DLC is located below
the instrument panel cover assembly. The DLC connector is used in assembly plants to receive information in
checking that the engine and transmission and other sub-systems are operating properly before they leave the
plant. The Diagnostic Trouble Code(s) stored in the PCM/PIM memory can be read with a Tech 2 scan tool.
CLEARING THE DTCS
To clear a current Diagnostic Trouble Code from the memory of the PCM, the PCM power feed must be
disconnected for at least ten (10) seconds, or the Tech 2 scan tool must be used. The battery power feed can be
disconnected by:
• Disconnecting the negative battery terminal
• Removing the Fuse F31 in the engine compartment fuse/relay panel.
The Tech 2 scan tool has a special mode that can be used to clear both history and current diagnostic trouble
codes. This mode is labeled Clear DTC Information found under Diagnostic Trouble Codes.
NOTE: To prevent PCM damage, the ignition must be OFF when disconnecting or reconnecting PCM power.
CLEARING THE DTC HISTORY CODE
The Tech 2 scan tool is the only tool capable of clearing the DTC history code. Disconnecting the battery will not
erase DTC history. The Tech 2 scan tool sends a special message to the PCM to erase the DTCs.
IGNITION CYCLE DEFAULT
If the ignition is c ycled (O FF and ON) 50 tim es without a particular fault resetting, that DT C will be c leared from the
PCM memory and the ignition cycle counter in the PCM will reset to zero.
PCM SLEEP TEST
After the ignition s witch is turned OFF the PCM will continue to operate for several seconds. During this shut down,
the PCM will set the IAC valve to a position to be used on the next startup, de-energising all the solenoids and
relays, etc. and go to sleep. The Tech 2 scan tool will display updated data until the sleep mode is activated then
the PCM will no longer send out serial data and the Tech 2 scan tool will display DLC Data Lost.
PCM LEARNING ABILITY
The PCM has a "lear ning" ability which allows the PCM to m a k e c or rec tions f or minor var iations in the engine or the
transmission system to improve driveability.
TRANSMISSION ADAPT FUNCTION
The HYDRA-MATIC 4L60-E uses a feedback line pressure control system which has the ability to adapt the
system's line pres sure to compens ate for nor m al wear of the c lutch plates, s eals, spr ings, etc. T his lear ning feature
is similar to what is used for engine fuel control, short term fuel correction, and long term fuel trim.
The HYDRA-MATIC 4L60-E transm ission only uses the adapt function for the 1-2 up-shift. The PCM monitors the
engine speed to determine if the shift is occurring too fast (harsh) or too slow (soft). The PCM will adjust the
pressure control solenoid to maintain the correct shift feel. The line pressure can adapt to values ranging from 35
kPa below, to 70 kPa above normal line pressure.
Whenever the battery is disconnected, the "learning" process resets. A change may be noted in the vehicle's
perfor m ance. T o teach the vehicle, r eset the IAC valve and ensure that the engine is at operating tem peratur e. The
vehicle should be driven at part throttle with moderate acceleration and idle conditions until normal performance
returns.
Diagnostic tables c ontain diagnosis procedures using a Tech 2 s can tool whenever possible. The T ech 2 scan tool
contains information about what is happening in the engine/transmission management system.
POWERTRAIN OBD SYSTEM CHECK
Step Action Value(s) Yes No
1 Ignition ON engine OFF.
Does the Check Powertrain Lamp (CPL) illuminate for at
least two seconds?
Go to Step 2 Go to Section
12C in VX
Service
Information for
CPL Diagnosis
2 1. Connect a Tech 2 scan tool to the Data Link
Connector (DLC).
2. Turn ON the ignition leaving the engine OFF.
Does the Tech 2 scan tool display Engine ID
Information?
Go to Step 3 Go to Data Link
Connector
Diagnosis Table
in This Section
3 1. Ignition ON, engine OFF.
2. Using the Tech 2 scan tool, are any PCM DTC(s)
displayed?
Go to the
applicable DTC
table
Go to Step 4
4 1. Ignition ON and wait for a minimum of five seconds.
2. Turn the key to the crank position.
Does the engine crank?
Go to Step 5 Go to Starter
Cranking Circuit
Table in This
Section
5 Does the engine start and continue to run? Go to Step 6 Go to Engine
Cranks But Does
Not Run Table in
this Section
6 Compare the Tech 2 scan tool data with the values
shown in the Engine Scan Data Engine Stream.
Are the values normal or within typical ranges?
Go to Step 7 GO TO
DIAGNOSTIC
AIDS AND TEST
DESCRIPTIONS
7 1. Check and record, then clear all DTC(s) from PCM,
BCM, and PIM.
2. Retest vehicle.
NOTE:
Insure that the vehicle has been road tested long enough
to meet the customers complaint, or for all control
module system diagnostics to have run.
3. Using the Tech 2 scan tool, re-test for any
reoccurring
DTC(s).
Did any DTC(s) reset?
System OK Go to Step 1
Figure 6C3-2-8 Example of Powertrain On-Board Diagnostic (OBD) System Check
POWERTRAIN OBD SYSTEM CHECK
After the vis ual and physical underhood ins pection, the POW ERTRAIN O BD SYST EM CHECK is the starting point
for all diagnostic procedures or finding the cause of an emissions test failure.
All diagnostic procedures must always begin with the POWERTRAIN OBD SYSTEM CHECK.
Diagnostic procedures mus t begin with the POWERTRAIN O BD SYSTEM CHECK, which represents an or ganised
approach for identifying system problems.
The POWERTRAIN OBD SYSTEM CHECK makes an initial check of the system and directs the technician to other
tables of the VX Series Service Information. It must be used as a starting point for all procedures. The entire
Section is set up in a specific order. The POW ERTRAIN OBD SYSTEM CHECK will lead the technician to other
tables, and those tables may lead to still other tables. THE SEQUENCE MUST BE FOLLOWED. The
engine/transmission control system uses many input signals and controls many output functions. If the correct
diagnostic sequence is not followed, incorrect diagnosis and replacement of serviceable parts may occur.
Diagnostic tables incorporate diagnosis procedur es using a T ech 2 s can tool where poss ible. This T ech 2 sc an tool
is a sm all hand-held computer in its elf. Its func tion is to give inform ation to a technic ian about what is happening in
the powertrain management system.
The Data Link Connector (DLC) is us ed by the assembly plant to perform end of line tests . This connector can also
be used by technician to monitor certain inputs and outputs as seen by the Electronic Control Module (PCM). The
Tech 2 scan tool reads and displays the information (serial data) supplied to the data link connector from the
Powertrain Control Module (PCM).
The correct procedure to diagnose a problem is to follow three basic steps.
1. Are the On-Board Diagnostics working?: This is determined by performing the Powertrain OBD System
Check. Since this is the starting point for the diagnostic procedures or finding the cause of a failure, always
begin here.
If the On-Board Diagnos tics aren't work ing, the Powertrain OBD System Chec k will lead to a diagnostic table in
this section to correct the problem. If the On-Board Diagnostics are working correctly, the next step is:
2. Is there a Diagnostic Trouble Code stored?: If a diagnostic trouble code is stored, go directly to the
numbered diagnostic trouble code table of the VX Series Service Information. T his will determine if the fault is
still present. If no diagnostic trouble code is stored, then:
3. Observe Serial Data transmitted by the PCM: This involves reading the information available on the Serial
Data Stream with a Tech 2 scan tool. Information on this tool and the meaning of the various displays can be
found in the suc ceeding paragraphs. T ypical data readings under a particular operating condition c an be found
on the TECH 2 SCAN TOOL DATA pages.
DLC TECH 2 SCAN TOOL
The PCM can communicate a variety of information through DLC connector. This data is transmitted at a high
frequency which requires a Tech 2 scan tool for interpretation.
TECH 2 SCAN TOOL EXPLANATION
To ex plain how the T ech 2 scan tool work s, let's think for a minute about how a television work s. A televis ion is an
electronic device that receives and processes information and sends out information in a form that can be
understood by the person watching it. The televis ion rec eives a signal ( f rom a tr ansmitting st ation) that is not us able
to the person.
The television processes it, then sends the signal to a screen. The person can then see the information that the
television transmitting station sent out. The Tech 2 scan tool is like the television because it processes the
information sent to it by the PCM.
The information is sent out of the PCM to the Data Link Connector (DLC) serial data line. The Tech 2 scan tool
plugs into the data link connector and the information is sent to the tool on its cable. The Tech 2 scan tool
processes the information and "sends" the signal to a display screen on the tool.
Just like a television, you can select which "station" that you want to see. The difference is, instead of seeing the
picture on a television, you "see" the display screen. The "stations" that you can select on a T ech 2 scan tool are
the different input and output signals that are being processed by the PCM.
The Tech 2 scan tool for the GEN III V8 engine has the ability to send messages back to the PCM to do different
things s uc h as switch outputs O F F and O N. This allows the tec hnician to c ontrol the PCM. This c ontr ol only lasts as
long as the Tech 2 scan tool is connected.
TECH 2 SCAN TOOL USES - POWERTRAIN CONTROL MODULE (PCM)
The T ech 2 scan tool is a us eful and quick way of compar ing oper ating param eters of a poorly operating engine or
transmission with a known good one. For example, a sens or may shift its value but not s et a DT C. Comparis on with
a known good vehicle may uncover this problem.
The T ech 2 scan tool allows a quick check of sensors and switches which are inputs to the PCM. The PCM in the
vehicle sends out inf orm ation to the T ech 2 s can tool at a very fast rate ( Class II ser ial data), and the display on the
tool can update quicker than a digital multimeter. The Tech 2 scan tool allows a technician to manipulate wiring
harnesses or components under the vehicle while observing the T ec h 2 scan tool r eadout. This can help in locating
intermittent connections.
After you enter the proper vehicle information, the first display on the Tech 2 scan tool will ask for what type of
system to select from.
The following is a list of systems the Tech 2 will display:
F0: ENGINE
F1: TRANSMISSION
F3: CHASSIS
F4: BODY
After selecting F0: ENGINE, the scan tool will display:
V6
V6 Supercharge
V8
V8 GEN III
V6 LPG
DTC CHECK
Other
Once the correct engine has been selected, the Tech 2 scan tool will now have five test modes for diagnosis and
service of the PCM system. The five test modes are as follows:
MODE F0: DIAGNOSTIC TROUBLE CODES
In this test mode, DTCs stored by the PCM maybe displayed or cleared. When entering this mode there are four
modes:
F0. READ DTC INFO ORDERED BY PRIORITY:
DTC will be displayed in the order of priority.
F1. CLEAR DTC INFORMATION: Clears all DTC(s) in the vehicle’s PCM memory. Also clears Freeze
Frame/Failure Records, so before clearing codes, be sure to retrieve Freeze Frame / Failure Records.
F2. DTC INFORMATION: Shows codes which are set that match the criteria. Each code has its own page of
information. If multiple codes are set, the user must page through the display of codes:
F0:HISTORY: This DTC search will display only DTCs that are stored in the PCM memory as valid faults,
but are currently not active.
F1: Check Powertrain Lamp (CPL) MESSAGE REQUESTED: This DTC search will display only DTCs
that are requesting the Check Powertrain Lamp/CPL to turn ON.
F2: LAST TEST FAILED: This DTC search will display only DTCs that failed the last time the test ran.
F3: T EST FAILED SINCE CODE CLEARED: This DTC search will display all DTCs that have reported
a test failure since the last time DTCs were cleared.
F4: NOT RAN SINCE CODE CLEARED: This DTC search will display only DTCs that have not ran
since DT Cs were las t cleared. Any displayed DTCs have not run, therefore their c ondition (passing
or failing) is unknown.
F5: FAILED THIS IGNITION: This DTC search will display all DTCs that have failed at least once during
the current ignition cycle.
F3:FREEZE FRAME / FAILURE RECORDS: Shows Freeze Frame / Failure Records information. Freeze
Frame / Failure Records are types of snapshots in the memory of the vehicle’s controller.
MODE F1: DATA DISPLAY
This mode displays data parameters for the controller being diagnosed. When entering this mode, there are two
modes:
F0: ENGINE DATA: In this test mode, the Tech 2 scan tool continuously monitors system data, such as
engine speed data, engine coolant temperature etc.
F1: FUEL TRIM DATA: In this test mode, the Tech 2 scan tool continuously monitors system data, such as
engine speed data, engine coolant temperature, HO2S, Fuel Trim Cell etc.
MODE F2: SNAPSHOT
In this test m ode, the Tec h 2 scan tool captur es data before and after a snaps hot triggering condition whic h may or
may not set a DTC.
MODE F3: MISC. TESTS
In this test mode, the Tech 2 scan tool performs software override commands of the PCM, to assist in problem
isolation during diagnostics:
F0: OUTPUT TESTS
F0: FUEL PUMP
F1: A/C CLUTCH
F2: Check Powertrain Lamp (CPL)
F3: HIGH FAN
F4: CANISTER PURGE
F1: IAC SYSTEM
F0: RPM CONTROL: Used to control engine RPM from 600 RPM to 1675 RPM.
F1: IAC CONTROL: Used to control IAC steps from 0 to 120.
F2: IAC RESET: Used to reset IAC if the IAC is lost or if IAC has been replaced.
F3: BASE IDLE: Used to set the engine to base idle.
F2: RESET CELLS
Resets all LT Fuel Trim values to 0%
F3: 02 LOOP STATUS
With the engine running, Open or Closed Loop fuel control can be commanded.
With the engine running, forces air fuel ratio from 11.7 to 17.7.
MODE F4: FUNCTIONS TESTS
This mode performs functional tests on the PCM system which help verify proper operation. In this mode, fault
conditions are automatically logged by the Tech 2 scan tool.
The Tech 2 scan tool also has the ability to send commands to the PCM, instructing the PCM to perform various
functions or tasks. This provides a quick way to determine if a device is operational or not. In the F4 mode, the
following tests can be performed:
F0: IAC CIRCUIT: Designed to c onfirm IAC motor f unctions OK and is not los ing track of position. Monitors the
engine speed. Repeatedly cycles the IAC m otor in and out and then m onitors the engine speed. If OK, turn
ignition OFF and start repeatedly, then stabilise idle. If the value of final idle RPM is greater than a
calibrated threshold, then the IAC circuit has failed.
F1: PW R (POW ER) BALANCE: Designed to identify low power output from individual cylinders. Automatically
cycles each injector OFF and ON while monitoring and recording the RPM drop for each cylinder.
F3: WRNG (WIRING) HARNESS: Designed to confirm no intermittent open or short circuits exist in selected
circuits . Engine is at idle in N. T echnician s hould wiggle powertrain harness. T he T ech 2 scan tool monitors
inputs that should rem ain relatively static at idle such as: ECT, IAT , T P Sensor, VSS, CAM signal present,
18X signal present, EST lines, injector voltage m onitor, battery, ignition. If discontinuity occurs, the Tech 2
scan tool logs DTC and prompts technician to check the appropriate circuit.
F2: FUEL INJECT OR BALANCE: Des igned to check f unction of each injec tor while the engine is not running. A
fuel pres sure gauge has to be connec ted to the fuel rail and pres sure drop has to be recorded after turning
ON each injector.
TECH 2 SCAN TOOL USES - POWERTRAIN INTERFACE MODULE (PIM)
The PIM in the vehic le sends out inform ation to the T ech 2 scan tool at a ver y fast rate (UART serial data), and the
display on the tool can update quicker than a digital multimeter. The Tech 2 scan tool allows a technician to
manipulate wiring harnesses or components under the vehicle while observing the Tech 2 scan tool readout. This
can help in locating intermittent connections.
After you enter the proper vehicle information, the first display on the Tech 2 will ask for what type of system to
select from.
The following is a list of systems the Tech 2 will display:
F0: ENGINE
F1: TRANSMISSION
F2: CHASSIS
F3: BODY
After selecting F3: BODY, the scan tool will display:
Body Control Module
Powertrain Interface Module
SRS
Instrument
Electronic Climate Control
DTC Check
Other
Once the PIM has been selected, the Tech 2 scan tool will now have five test modes for diagnosis and service of
the PIM system.
The five test modes are as follows:
MODE F0: PIM NORMAL MODE
In this test mode, the scan tool monitors data sent from the PIM to other vehicle system control modules on the
serial data line. This data represents the normal bus communication executed during ignition ON. The PIM keeps
the other control modules that are connected on the serial data line informed about the status of the PCM
parameters. These parameters are collected from the PIM via serial data communication with the PCM.
The Engine Check Powertrain Lamp (CPL) in the instrument cluster is driven only with this status report in the
PIM's Normal Mode bus message. If PCM Check Powertrain Lamp (CPL) status report indicates OFF, the Check
Powertrain CPL on the instrument panel should be OFF.
The following PIM Normal Mode controller usage table indicates specific Control Modules using the PCM supplied
report status information:
PIM NORMAL MODE CONTROLLER USAGE TABLE
PIM Normal Mode
Scan Tool Parameters Used by:
Scan Tool String BCM INST ECC ABS/
ETC
Engine Speed √
√√
√
Coolant Temperature √
√√
√
Barometric Pressure *
Vehicle Speed √
√√
√
A/C Clutch
A/C Pressure √
√√
√
Low Speed Fan
Request √
√√
√
Low Fan Run ON √
√√
√
Theft Status √
√√
√
PCM DTC Sta tus √
√√
√
Check Powertrain CPL √
√√
√
Throttle Failure * √
√√
√
MAP Failure *
Fuel Used √
√√
√
Fuel Flow Rate √
√√
√
Engine Type √
√√
√
Transmission Coding
Fuel Type √
√√
√
Engine Oil Change √
√√
√
Transmission Oil
Change √
√√
√
Shift Pattern √
√√
√
Throttle Position * √
√√
√
High Coolant
Temperature
Low Coolant Level
* √
√√
√
Oil Pressure Sensor √
√√
√
PRNDL Switch √
√√
√
Commanded Gear √
√√
√
PCM Chime √
√√
√
* Indicates Only With GEN III V8 Engine
MODE F1: DIAGNOSTIC TROUBLE CODES
In this test mode, DTCs stored by the PCM maybe displayed or cleared. When entering this mode there are two
modes:
F0. READ CURRENT DTC INFORMATION: DTCs will be displayed in the PIM by priority or in sequence.
F1. CLEAR DTC INFORMATION: The scan tool will clear all stored DTCs from the PIM memory.
MODE F2: DATA DISPLAY
In this tes t mode, the T ec h 2 s c an tool continuous ly monitors s ystem data s uc h as : star ter relay, password learning,
engine oil change etc.
MODE F3: SNAPSHOT
In this test m ode, the Tec h 2 scan tool captur es data before and after a snaps hot triggering condition whic h may or
may not set a DTC.
MODE F4: MISC. TESTS
In this test mode, the Tech 2 scan tool performs software override commands of the PIM to assist in problem
isolation during diagnostics.
F0: OUTPUT TESTS
F0: STARTER RELAY
TECH 2 SCAN TOOL USE WITH INTERMITTENT FAULTS
The T ech 2 scan tool allows m anipulation of wiring harnesses or c omponents under the bonnet with the engine not
running, while observing the Tech 2 scan tool readout.
The T ech 2 s can tool can be plugged in and obs erved while driving the vehicle under the condition when the Check
Powertrain Lamp (CPL) turns ON momentarily or when the engine driveability is momentarily poor. If the problem
seems to be related to certain parameters that can be checked on the Tech 2 scan tool, they should be checked
while driving the vehicle. If there does not seem to be any connection between the problem and any specific circ uit,
the Tech 2 scan tool can be used to monitor each parameter, watching for a period of time to see if there is any
change in the readings that indicates an intermittent condition.
The Tech 2 scan tool can capture and store data when the problem occurs, so it can be played back at a slower
rate to determine what happened to the system. This is called the SNAPSHOT mode.
The Tech 2 s can tool is an easy way to compar e the operating parameters of a poorly operating engine with thos e
of a known good one. For example, a sensor may shift in value but not set a DTC. Comparing the sensor's readings
with those of a known good vehicle may uncover the problem.
The Tech 2 s can tool s aves time in diagnosis and helps to pr event the replac ement of ser viceable par ts . T he key to
using the Tech 2 s c an tool s ucc es s f ully is the tec hnic ian's ability to understand the system being diagnos ed, as well
as understanding the Tech 2 scan tool operation and its limitations. The technician should read the Tech 2
operator’s manual to become familiar with the Tech 2 scan tool operation.
With an understanding of the data which the tool displays, and knowledge of the circuits involved, the tool can be
very useful in obtaining information which would be more difficult or impossible to obtain with other equipment.
The T ech 2 scan tool does not make the use of diagnostic tables unnecessary, nor can it indicate exactly where a
problem is in a particular circuit. Diagnostic Tables inc orporate diagnosis pr ocedures that require the use of a Tech
2 scan tool.
TECH 2 SCAN TOOL LIMITATIONS
The T ech 2 sc an tool must r eceive the signal fr om the PCM in order to display any useable inform ation. If the PCM
sends no signals to the data link connec tor, or the connection to the T ech 2 sc an tool is defec tive, the Tech 2 scan
tool will only display, WAITING FOR DATA - NO DATA RECEIVED FROM PCM. The Powertrain OBD System
Check instructs the technician what to do if this happens.
The T ech 2 sc an tool has a few lim itations. If the T ech 2 sc an tool is displaying a PCM "output" f unction, it displays
only the comm and given by the PCM. That does not mean that the desired action took place. This is similar to the
automatic transmission dashboard gearshift indicator. Just because the gearshift P R N D L pointer indicates the
transm ission is in DRIVE does not mean that the transmis sion is actually in that gear . To be sure, you must c heck
the linkage and adjustment at the transmission.
When using the T ech 2 s c an tool to obs erve one of the PCM "output" functions, s uc h as an idle air c ontrol motor , or
a TCC s olenoid, the technician must not assume the indic ated is the same as the actual. If the Tec h 2 scan tool is
displaying TCC solenoid as being ON, but the wire to power it is disconnected or defective, the PCM in som e cas es
has no way of knowing it. The display may indicate the command is ON, but the device may not be operating!
The Tech 2 s can tool s aves time in diagnosis and helps to pr event the replac ement of ser viceable par ts . T he key to
using the Tech 2 scan tool successfully for diagnosis is the technician's ability to understand the system being
diagnosed, as well as an understanding of the Tech 2 scan tool's limitations.
With an understanding of the data the Tec h 2 scan tool dis plays, and knowledge of the circuits involved, the Tech 2
scan tool is useful in obtaining information which is difficult or impossible to retrieve with other methods.
Remem ber, the Tech 2 scan tool does NOT make using diagnostic tables unnecessary, nor can it tell you exactly
where a problem is in a circuit. Most diagnostic tables incorporate diagnosis procedures that require the use of a
Tech 2 scan tool.
TECH 2 SCAN TOOL: PIM NORMAL MODE
The Tech 2 scan Tool PIM Normal Mode in the table may be used for comparison if a status report is being sent
from the PIM.
1. After completing the Powertrain OBD System Check
2. Finding the on-board diagnostics are functioning properly and
3. No diagnostic DTCs are displayed.
IMPORTANT:
Do not use a T ech 2 sc an tool that displays faulty data. Report the condition to the sc an tool manufac turer. The use
of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts. Only the parameters
listed below are used of the VX Series Service Information for diagnosing. If a scan tool displays other parameters,
the values are not recommended by Holden for use in diagnosis.
NOTE:
Only the parameters listed ar e us ed in this VX Series Servic e Inf or mation for diagnos is . For m or e descr iption on the
values and use of the Tech 2 scan tool to diagnosis PCM/PIM inputs, r efer to the applicable diagnosis table in this
VX Series Service Information. If all values are within the range illustrated, refer to SYMPTOMS Tables in
Section 6C3-2B of the VX Series Service Information.
Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan Data Engine Stream table.
1. T he Tech 2 sc an tool FO: PCM/PIM NORMAL MOD E will dis play scan positions that will be displayed in order.
The Tech 2 sc an tool will dis play nine (9) scan position par ameters at a time. T he down arrow button will scroll
down through all of the scan positions one at a time. After TIME FROM START parameter is displayed,
pressing the down arrow button again will display scan position parameters starting at the top of the list again.
2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a
value that is being sensed or being issued by the PCM.
3. T YPICAL DAT A VALUE is separated into two parts. T hese displayed values are typic al of a norm ally operating
vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a
failure. The ENGINE RUNNING data should be com pared to the IGNITION ON data as a diagnostic check to
make sure the component or system is operating properly.
4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON
and engine stopped. Temperature sensors should be compared to the actual temperatures by allowing the
sensor to cool overnight and then comparing their values. A difference of 3-5° C from the actual temperature
may indicate a problem with the sensor. Us e the diagnostic aids table for that sensor to compar e the resistance
to temperature values.
1. ENGINE RUNNING typical data values are an average of display values recorded from normally operating
vehicles at normally operating temperature. They are intended to represent what a normally functioning system
would typically display.
TECH 2 SCAN TOOL: PIM NORMAL MODE
TYPI CAL DATA VALUE S
SCAN POSITION Q UNITS DISPLAYED R IGNITION ON T ENGINE RUNNING U
ENGINE SPEED RPM 0 RPM 600 - 650 RPM
(± 50 RPM IN DRIVE )
COOLANT TEMPERATURE DEGREES C Varies +96 C
BAROMETRIC PRESSURE
kPa 0 to 200 kPa
(VARIES) 0 to 200 kPa
(VARIES)
VEHICLE SPEED km/h 0 0
A/C CLUTCH ON /OFF OFF OFF
A/C PRE S SURE kPa 896 kPa 800 - 1000 kPa A/C OFF
1600 - 1900 kPa A/C ON
LOW SPEED FAN REQUEST ON / OFF OFF OFF
LOW FAN RUN ON YES / NO NO NO
THEFT STATUS (only BCM-PIM) NO START / START START START
PCM DTC STA T US NO DTC(s)/DTC(s)
SET NO DTC(s) NO DTC(s)
CHECK POWERTRAIN
LAMP (CPL) OFF/ON ON OFF
THROTTLE FAILURE YES/NO NO NO
MAP FAI LURE YES/NO NO NO
FUEL USED L 00.00 1 - 2 L/Hour
FUEL FLOW RATE 00.00 1 - 2 L/Hour
ENGINE TYPE V6, V8,
V6 SUPERCHARGE,
V8 GEN 3
V8 GEN 3 V8 GEN 3
TRANSMISSION CODING MANUAL TRANS.
AUTO TRANS. MANUAL TRANS.
AUTO TRANS. MANUAL TRANS.
AUTO TRANS.
FUEL TYPE PETROL / LPG PETROL PETROL
ENGINE OI L CHA NGE OKAY /
SERVICE REQUIRED OKAY OKAY
TRANSMISSION OIL CHANGE OKAY /
SERVICE REQUIRED OKAY OKAY
SHIFT PATTERN POW ER/ECONOMY ECONOMY ECONOMY
THROTTLE POSI TI ON 0-100 % 0% 0%
HIGH COOLANT TEMPERATURE YES/NO NO NO
LOW COOLANT LEVEL YES/NO NO NO
OIL PRESSURE S E NS OR OFF/ON OFF OFF
PRNDL SWITCH INVALID /
P,R,N,D,3,2,1 INVALID
OR
GEAR SELECTED
INVALID
OR
GEAR SELECTED
COMMANDED GEAR P/N R, 1 P/N P/N
PCM CHIME YES/NO YES YES
TECH 2 SCAN TOOL: PIM NORMAL MODE DESCRIPTIONS
A list of ex planations for each data me ssage displayed on the Tech 2 s can tool is listed below. T his inform ation will
assist in diagnosing emis sion or dr iveability pr oblem s. T he displays can be viewed while the vehicle is being driven.
Refer to the Powertrain OBD System Check for additional information.
ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM
The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired
idle speed under various engine loads with engine idling.
COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)
The Engine Coolant T emperature (ECT ) Sensor is mounted in the cylinder head of the left bank . The PCM apples
5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature
changes. W hen the sensor is cold ( internal resistanc e high), the PCM monitor s a high signal voltage and interprets
the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases
and the PCM interprets the lower voltage as a warm engine.
BAROMETRIC PRESSURE (BARO) SENSOR: Tech 2 Displays a range of 0 to 200 kPa / 0 to 5.0 volts
The BARO reading is displayed in volts and kPa and represents the altitude of the vehicle for the transmission
control. At sea level the BARO reading is about 4.7 to 4.9 volts. At 3048 m eters (10,000 feet) the BARO reading is
about 2.5 to 3.0 volts.
* ( Only with GEN III V8 Engine)
VEHICLE SPEED: Tech 2 Displays a range of 0 to 255 km/h
The vehicle speed sensor signal is converted into km/h and mph for display.
A/C CLUTCH: Tech 2 Displays "ON" or "OFF"
Represents the commanded state of the A/C clutch control relay. Clutch should be engaged when ON is displayed.
A/C PRESSURE: Tech 2 Displays a range of 0 to 3195 kPa
The kPa displayed indicates that the PCM is monitoring an A/C Refrigerant Pressure signal voltage which is too
high or too low to allow the A/C compressor clutch to engage.
LOW SPEED FAN REQUEST: Tech 2 Displays "ON" or "OFF
Indicates if the engine cooling fan low speed relay has been commanded ON or OFF.
LOW FAN RUN ON: Tech 2 Displays "NO" or "YES"
This indicates if the PCM is requesting the BCM to turn the Low Speed Fan ON at key OFF.
THEFT STATUS: Tech 2 Displays "NO START" or "START"
Indicates the status of the Theft Deterrent System.
PCM DTC STATUS: Tech 2 Displays "NO DTC(s)" or “DTC SET”
Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC are or are not set.
CHECK POWERTRAIN LAMP (CPL) or MALFUNCTION INDICATOR LAMP (MIL): Tech 2 Displays "OFF" or
"ON"
Indicated if the instrument panel Malfunction Indicator Lamp is ON or OFF.
THROTTLE FAILURE: Tech 2 Displays "NO" or "YES"
Indicates if the throttle position sensor has failed. This is reported from the PCM to the PIM.
* (Only with GEN III V8 Engine)
MAP FAILURE: Tech 2 Displays "NO" or "YES"
Indicates if the Map sensor has failed. This is reported from the PCM to the PIM.
* (Only with GEN III V8 Engine)
FUEL USED: Tech 2 Displays a range of 0 to 1000 Litres
When the key is turned ON and the engine is running, the PCM will calculate FUEL USED during each ignition
cycle.
FUEL FLOW RATE: Tech 2 Displays a range of 0 to 100 litres
Indicates fuel consumption per litres per hour.
ENGINE TYPE: Tech 2 Displays Engine Type
The Tech 2 uses this information for proper Tech 2 scan tool software.
TRANSMISSION CODING: Tech 2 Displays “MANUAL” or “AUTOMATIC”
The Tech 2 uses this information for proper Tech 2 scan tool software
FUEL TYPE: Tech 2 Displays “PETROL” or “LPG”
The scan tool will display what fuel type the PCM software is set up for.
ENGINE OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”
The scan tool will display the status of the engine oil change condition.
TRANSMISSION OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”
The scan tool will display the status of the transmission oil change condition.
SHIFT PATTERN: Tech 2 Displays “ECONOMY” or “POWER”
This display shows the state of the POWER/ECONOMY switch.
THROTTLE POSITION: Tech 2 Displays a range of 0 to 100%
Computed by the PCM from TP sensor voltage (T hrottle Position) should read 0% at idle and 100% at Wide Open
Throttle (WOT).
* (Only with GEN III V8 Engine)
HIGH COOLANT TEMPERATURE: Tech 2 Displays "NO" or "YES"
This is an indication to the PCM that the engine is running hot.
LOW COOLANT LEVEL: Tech 2 Displays "NO" or "YES"
This is an indication to the PCM that the coolant level is low, and the PCM will turn on the Low Coolant lamp.
* (Only with GEN III V8 Engine)
OIL PRESSURE SENSOR: Tech 2 Displays "OFF" or "ON"
This is an indication to the PCM if the oil pressure is high or low. If the oil pressure is low, the PCM will turn on a
Low Oil Warning Lamp.
PRNDL SWITCH: Tech 2 Displays “INVALID” or “P, R, N, D, 3, 2, 1”
This displays if the vehicle is not equipped with a PRNDL switch (INVALID), or if equipped, indic ates what gear the
driver has selected.
COMMANDED GEAR: Tech 2 Displays “1, 2, 3, 4”
The gear that the PCM is com m anding the tr ansm iss ion to be in. In PARK, the Tec h 2 scan tool will display "1", the
commanded state of the shift.
PCM CHIME: Tech 2 Displays "NO" or "YES"
This is a indication to the instrument panel allowing the instrument panel to chime if a problem or fault is detected.
TECH 2 SCAN TOOL: ENGINE DATA
The Tech 2 scan Data listed in the table may be used for comparison
1. After completing the Powertrain OBD System Check
2. Finding the on-board diagnostics are functioning properly and
3. No diagnostic DTCs are displayed.
A TECH 2 SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM
SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY TECH 2 SCAN TOOL CAN
RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.
Only the parameters listed are us ed in the VX Series Service Inform ation f or diagnosis. For m ore description on the
values and use of the Tech 2 scan tool to diagnosis PCM inputs, refer to the applicable diagnosis table of the VX
Series Service Information. If all values are within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-
2B of the VX Series Service Information.
Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan Data Engine Stream table.
1. T he Tech 2 s c an tool F2: DATA LIST will display scan positions that will be displayed in order. T he T ec h 2 s c an
tool will display nine ( 9) scan position param eters at a tim e. The down arrow button will scroll down through all
of the sc an positions one at a tim e. Af ter T IME FR OM ST ART par am eter is displayed, pressing the down arrow
button again will display scan position parameters starting at the top of the list again.
2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a
value that is being sensed or being issued by the PCM.
3. T YPICAL DAT A VALUE is separated into two parts. T hese displayed values are typic al of a norm ally operating
vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a
failure. The ENGINE RUNNING data should be com pared to the IGNITION ON data as a diagnostic check to
make sure the component or system is operating properly.
4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON
and engine stopped. T emperature s ens ors s hould be compared to the ac tual temperatur es by letting the sensor
stabilise overnight and then comparing their values. A difference of 3-5° C from the actual temperature may
indicate a problem with the sensor. Use the diagnostic aids table for that sensor to com pare the resistance to
temperature values.
5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating
vehicles at norm ally operating tem perature. T hey are intended to represent what a norm ally functioning system
would typically display.
TECH 2 SCAN TOOL: ENGINE DATA
TYPI CAL DATA VALUE !
SCAN POSITION " UNITS DISPLAYED # IGNITION ON $ ENGINE RUNNING %
ENGINE SPEED RPM 0 RPM ± 100 RP M FROM DES IRED RPM
(± 50 RPM IN DRIVE )
DESIRED IDLE S P EED RPM 0 RPM PCM IDLE COMMAND (VA RIES WITH
TEMPERATURE)
ENG. COOLANT TEMP (ECT) DEGREES C VARIES +96° C
START UP ECT DEGREES C VARIES VARIES
IAT DEGREES C VARIES VARIES
MAP SENSOR kPa VARIES VARIES
MAP SENS OR V OLTS VOLTS 4.6 Volts 1 to 2 Volts
MASS AI R FLOW GRAM /SEC 0 g/s 5 -10 g/s
MAF SENSOR FREQUENCY Hz 0 Hz 2200-2500 Hz
BARO kPa VARIES VARIES
BARO SENS OR V OLTS VOLTS 4.6 VOLTS 4.5 VOLTS
THROTTLE POSI TI ON 0-100 % 0 % 0 %
THROTTLE POSI TI ON SENSOR VOLTS 0.32 V 0.47 V
FUEL SYSTEM STATUS OPEN LOOP/
CLOSED LOOP OPEN LOOP CLOSED LOOP
INJECTION PULSE BANK 1 mS 0.00 mS 3.00 - 3.50 mS
INJECTION PULSE BANK 2 mS 0.00 mS 3.00 - 3.50 mS
AIR FUEL RA TI O % 0.01 14.7:1
SPARK ADVANCE DEGREES 0°BTDC 13° BTDC
IGNITION COIL CYL. 1 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 2 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 3 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 4 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 5 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 6 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 7 OKAY / FAULT OKAY OKAY
IGNITION COIL CYL. 8 OKAY / FAULT OKAY OKAY
KNOCK PRESENT YES / NO NO NO
KNOCK RETARD DEGREES 0° 0°
CAMSHAFT ACTIV ITY COUNTS 0 INCRUMENTING FROM 0 UP TO 65535
PURGE PWM % 0% 17%
HIGH SPEED FAN OFF / ON OFF OFF
A/C REQUEST YES / NO NO NO
A/C CLUTCH ON / OFF OFF OFF
A/C PRE SSURE kPa 1151 kPa 1091 k P a
REVERS E LOCK -OUT SOL ON/OFF ON ON
TRANSMISSION RANGE PARK, REVERSE,
NEUTRAL, DRIVE 4
OD, DRIVE 3 / D,
DRIVE 2, DRIVE 1,
INVALID
PARK PARK
COMMANDED GEAR 1,2, 3, 4 1 1
TCC SOLENOID ON / OFF OFF OFF
TCC PWM SOLENOID % 0% 0%
TCC BRAKE SWITCH ON / OFF OFF OFF
ENGINE OI L PRESSURE PSI 39 PSI 200 - 225 PSI
ENGINE OIL PRESSURE VO LTS 0.7 VOLTS 1.5 V OLTS
THEFT STATUS NO START / START START START
ENG. COOLANT LEVEL SWITCH ON / OFF OFF OFF
IDLE AI R CONTROL STEP S 169 52
DESIRE D IAC AI RFLOW 0-64 g/s 9.4 g/s 5.8 g/s
VEHICLE SPEED km/h 0 0
BATTERY VOLTAGE volts 12 14
DTC STA T US NO DTC / DTCs SET NO DTC NO DTC
TIME FROM START TIME 0:00:00 VARIES
TECH 2 SCAN TOOL: ENGINE DATA DESCRIPTIONS
A list of ex planations for each data me ssage displayed on the Tech 2 s can tool is listed below. T his inform ation will
assist in diagnosing emis sion or dr iveability pr oblem s. T he displays can be viewed while the vehicle is being driven.
Refer to the Powertrain OBD System Check for additional information.
ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM
The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired
idle under various engine loads with engine idling.
DESIRED IDLE SPEED: Tech 2 Displays a range of 0 to 3175 RPM
The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the
engine at the desired idle speed.
ENGINE COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)
The Engine Coolant T emperature (ECT ) Sensor is mounted in the cylinder head of the left bank . The PCM apples
5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature
changes. W hen the sensor is cold ( internal resistanc e high), the PCM monitor s a high signal voltage and interprets
the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases
and the PCM interprets the lower voltage as a warm engine.
START UP ECT: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)
The s can tool dis plays the Engine Coolant Temperature at the time the engine was s tarted. The PCM uses Start Up
ECT for certain DTCs.
IAT: Tech 2 Displays a range of -39°C to 104°C (-38°F to 284°F)
The PCM converts the resistance of the Intake Air Temperature Sensor to degrees. The PCM uses the Intake Air
Temperature (IAT) in order to adjust fuel delivery and spark timing according to incoming air density.
MAP: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.0 volts
The Manifold Absolute Pressure (MAP) Sensor measures the change in the intake manifold pressure from engine
load and speed changes. As the intake manifold pressure increases, the intake vacuum decreases resulting in a
higher MAP sensor voltage and kPa reading. The PCM uses the MAP sensor signal f or the following: (1) Updating
the BARO reading; (2) Enabling factor for several of the diagnostics.
MASS AIR FLOW: Tech 2 Displays a range of 0 to 246 Grams/Sec
The Mass Air Flow (MAF) sensor measures the change in the intake air flow which results from engine load and
speed changes. As intake air flow increases, the air in the inlet manifold also increases and addition fuel is required.
MAF: Tech 2 Displays a range of 0 to 10,192 Hz
The signal that is sent from the Mass Air Flow (MAF) sensor to the PCM is in the form of a frequency output. This
frequency output changes as the demand of engine air intake changes.
BARO: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.00 Volts
The Barometric Pressure reading is determined from the MAP sensor signal. The PCM monitors the MAP signal
during key up and Wide Open Throttle (WOT) conditions. The Barometric Pressure compensates for altitude
differences.
TPS ANGLE: Tech 2 Displays a range of 0 to 100%
Computed by the PCM from the TP sensor voltage. The TP angle should read 0% at idle to greater than 80% at
Wide Open Throttle.
TPS VOLTAGE: Tech 2 Displays a range of 0 to 5.10 Volts
Used by the PCM to determine the amount of throttle demanded by the driver. The TPS voltage should read
between 0.25 - 1.25 volts at idle to greater than 4 volts at wide open throttle.
FUEL SYSTEM STATUS: Tech 2 Displays “OPEN LOOP” or “CLOSED LOOP”
CLOSED LOOP indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In OPEN
LOOP, the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on TP sensor,
engine coolant, and MAF sensor inputs only.
INJECTION PULSE BANK 1 / BANK 2: Tech 2 displays a range of 0 to 100 m/sec
The Inj ector average indicated the am ount of tim e the PCM com m ands each injector ON during each engine cycle.
A longer injector pulse with causes more fuel to be delivered. The Injector Pulse Width increases with increased
engine load.
AIR /FUEL RATIO: Tech 2 Displays a range of 0.00 : 99.99
The Air Fuel ratio is determined from the Heated Oxygen Sensor output. The PCM uses the fuel trim to adjust
fueling to attempt to maintain an air f uel r atio of 14.7:1. A lower value indica tes a r icher c ommanded air f uel mixtur e
while a higher value indicates a leaner mixture.
SPARK ADVANCE: Tech 2 Displays a range of -64 to 64°
The scan tool displays the amount of degrees the PCM com mands the spark advance on the Ignition Control (IC)
circuit. The PCM computes the desired spark advance using the following: (1) Engine Coolant Temperature; (2)
Engine Speed (RPM); (3) Load; (4) Vehicle Speed. The PCM adjusts the timing.
IGNITION COIL CYL. 1 through 8: Tech 2 Displays “OKAY” or “FAULT”
This indic ates if ther e is a f ault in a ignition c oil dr iver c irc uit. If a fault is pres ent, the Tech 2 will display FAULT, and
a DTC will set.
KNOCK PRESENT: Tech 2 Displays “YES” or “NO”
Indicates whether or not a knock signal is being detected by the PCM. Should read NO at idle.
KNOCK RETARD: Tech 2 Displays a range of 0.0° to 16°
Knock Retard indicates the am ount of s park the PCM rem oves f rom the IC spark advance in response to the signal
from the Knock Sensor.
CAMSHAFT ACTIVITY: Tech 2 Displays a range of 0 to 65535 counts
The counts increment as the PCM detects the Camshaft sensor signal voltage.
PURGE PWM: Tech 2 Displays a range of 0 to 100%
The PCM commands the PWM duty cycle of the EVAP Purge Solenoid valve. 0% displayed indicates no purge;
100% displayed indicates full purge.
HIGH SPEED FAN: Tech 2 Displays "OFF" or "ON"
Indicates if the engine cooling fan high speed relay has been commanded ON or OFF.
A/C REQUEST: Tech 2 Displays “YES” or “NO”
The A/C Reques t displays the st ate of the A/C r equest input c irc uit f r om the HVAC controls . T he PCM us es the A/C
request signal in order to determine whether the A/C compressor operation is being requested.
A/C CLUTCH: Tech 2 Displays “ON” or “OFF”
The A/C Clutch represents the commanded state of the A/C clutch control relay. W hen the scan tool displays ON,
the A/C clutch should be engaged.
A/C PRESSURE: Tech 2 Displays 15 to 452 psi/ 103 to 3116 kPa
This parameter represents the A/C Refrigerant Pressure Sensor signal. The amount of pressure indicates the
amount of load that the A/C c ompres sor plac es on the engine. The PCM uses this inf ormation in order to adj ust idle
and in order to control the cooling fans.
REVERSE LOCK-OUT SOL: Tech 2 Displays “ON” or “OFF”
This indicates the status of the manual transmission reverse lock-out solenoid. W hen the scan tool indicates ON,
the transmission can be shifted into reverse gear. W hen the scan tool indicates OFF, the transmission cannot be
shifted into reverse gear.
TRANSMISSION RANGE: Tech 2 Disp lays “Park/Neutral - Reverse - Driv e 4 - Drive 3 - Drive 2 - Drive 1” -or
“Invalid”
Tech 2 displays the transmission gear position.
COMMANDED GEAR: Tech 2 Displays “1-4”
Tech 2 displays which gear the transmission is in. An illegal transmission position displays 9.
TCC SOLENOID: Tech 2 Displays “ON” or “OFF”
Indicates if the TCC enable Solenoid is commanding the TCC ON or OFF.
TCC PWM SOLENOID: Tech 2 Displays “ON” or “OFF”
This parameter is the commanded state of the TCC PWM solenoid. The scan tool displays ON when the
commanded state of the solenoid requests ON. The scan tool displays OFF when the solenoid is not ON.
TCC BRAKE SWITCH: Tech 2 Displays “ON” or “OFF”
This param eter indic ates the state of the T CC brak e s witch circuit input. T he s can tool displays ON when you apply
the vehicle brakes. The torque converter clutch disengages. The scan tool displays OFF when you release the
vehicle brakes. This allows the torque converter clutch to engage.
ENGINE OIL PRESSURE: Tech 2 Displays a range of 0 to 144 psi/0 to 992 kPa/0.0 to 5.0 Volts
The Engine Oil Pressure Sensor measures the engine oil pressure. As the RPM increases from the idle position,
the engine oil pressure will also increase. W hen the oil pressure reaches a predeterm ined low value, the PCM will
turn ON the Low Oil Warning lamp.
THEFT STATUS: Tech 2 Displays "NO START" or "START"
Indicates the status of the Theft Deterrent System.
ENGINE COOLANT LEVEL SWITCH: Tech 2 Displays “OFF” or “ON”
The scan tool will display ON if the coolant level is low. If the coolant level is normal, the scan tool will display OFF.
IDLE AIR CONTROL: Tech 2 Displays a range of 0 to 255 Counts
Displays the commanded position of the Idle Air Control pintle in counts. The higher the number of counts, the
greater the commanded idle speed. The Idle Air Control valve should respond quickly to changes in engine load.
DESIRED IAC AIRFLOW: Tech 2 Displays a range of 0 to 64 Grams Per Second (g/s)
This parameter displays the calculated airflow in the IAC passage.
VEHICLE SPEED: Tech 2 Displays a range of 0 to 255 km/h
The vehicle speed sensor signal is converted into km/h and mph for display.
BATTERY VOLTAGE: Tech 2 Displays a range of 0 to 25.5 volts
This represents the system voltage measured at the PCM.
DTC STATUS: Tech 2 Displays "NO DTC(s)" or “DTC SET”
Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.
TIME FROM START: Tech 2 Displays “0:00:00”
Indicates the hours, minutes and seconds the engine has been running.
TECH 2 SCAN TOOL: FUEL TRIM DATA
The Tech 2 scan Data listed in the table may be used for comparison
1. After completing the Powertrain OBD System Check
2. Finding the on-board diagnostics are functioning properly and
3. No diagnostic DTCs are displayed.
IMPORTANT:
Do not use a T ech 2 sc an tool that displays faulty data. Report the condition to the sc an tool manufac turer. The use
of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts. Only the parameters
listed below are used of the VX Series Servic e Inform ation for diagnos ing. If a scan tool dis plays other parameters ,
the values are not recommended by Holden for use in diagnosis.
NOTE:
Only the param eter s lis ted are us ed of the VX Ser ies Ser vice Inf or mation f or diagnosis . F or more des c r iption on the
values and use of the Tech 2 scan tool to diagnosis PCM inputs, refer to the applicable diagnosis table of the VX
Series Service Information. If all the values are within the range illustrated, refer to SYMPTOMS Tables in Section
6C3-2B of the VX Series Service Information.
Test Description The numbers below refer to the circled numbers on the diagnostic table.
1. The scan position refers to the Tech 2 scan tool FUEL TRIM DATA LIST that will be displayed in order.
2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a
value that is being sensed or being issued by the PCM.
3. TYPICAL DATA VALUE is separ ated into two par ts. These displayed values are typical of a norm ally operating
vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a
fault. The ENGINE RUNNING data should be compared to the IGNITION ON data as a diagnostic check to
make sure the component or the system is operating properly.
4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON
and the engine OFF. The temperature sensors should be compared to the actual temperatures by letting the
sensor stabilise overnight and then comparing their values. A difference of 3 to 5° C from the actual
temperature may indicate a problem with the sensor. Use the diagnostic aids table for that sensor to compare
the resistance to temperature values.
Som e ON or O FF s witches may display an abnor mal state. If the table s tates this position is abnormal, than this
may be caused by an open or short to earth, depending upon the normal state of the s witch. Ref er to the proper
Section of the VX Series Service Information for more information on diagnosis.
5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating
vehicles at norm ally operating tem perature. T hey are intended to represent what a norm ally functioning system
would typically display.
TECH 2 SCAN TOOL: FUEL TRIM DATA
TYPI CAL DATA VALUE !
SCAN POSITION " UNITS DISPLAYED# IGNITION ON $ ENGI NE RUNNING %
ENGINE SPEED RPM 0 RPM ± 100 RPM FROM DESIRED RPM
(± 50 RPM IN DRIVE)
DESIRED IDLE SPEED RPM 650 RPM PCM IDLE COMMAND (VA RI ES WI TH
TEMPERATURE)
ENGINE COOLANT
TEMPERATURE (ECT) °C VARIES 96°C
IAT DEGREES C VARIES VARIES
MAP SENSOR kPa VARIES VARIES
MAP SENSOR VOLTS VOLTS 4.5 V OLTS 4.5 VOLTS
MASS AI R FLOW GRAM /SE C 0 g/s 5 -10 g/s
MAF SENSOR FREQUENCY Hz 0 Hz 2600-2900 Hz
BARO kPa VARIES VARIES
BARO SENSOR VOLTS VOLTS 4.5 VOLTS 4.5 VOLTS
THROTTLE POSI TI ON 0-100 % 0 % 0 %
THROTTLE POSI TI ON SENSOR VOLTS 0.32 V 0.47 V
AIR FUEL RA TI O % 14. 7:1 14.7:1
FUEL SYSTEM STATUS OPEN LOOP/
CLOSED LOOP OPEN LOOP CLOSED LOOP
ENGINE LOA D % 0% 1%
LEFT HO2S SENSOR READY
(BANK 1) YES/NO NO YES
RIGHT HO2S SENSOR READY
(BANK 2) YES/NO NO YES
LEFT HO2S SENSOR
(BANK 1) mV 447mV 100-1000 mV AND V ARYING
RIGHT HO2S S ENSOR
(BANK 2) mV 447mV 100-1000 mV AND V ARYING
LEFT SHORT TERM FUEL TRIM
(BANK 1) % +0% to -0% +10% to -10%
RIGHT SHORT TERM FUEL TRIM
(BANK 2) % +0% to -0% +10% to -10%
LEFT LONG TERM FUEL TRIM
(BANK 1) % +0% to -0% +10% to -10%
RIGHT LONG TERM FUEL TRIM
(BANK 2) % +0% to -0% +10% to -10%
FUEL TRIM CELL CELL # 0 17
FUEL TRIM LEARN YES/NO NO YES
LEFT STFT AVERAGE
(SHORT TE RM FUE L T RIM) % 0% 0%
RIGHT STFT AVERAGE
(SHORT TE RM FUE L T RIM) % 0% 0%
LEFT LTFT AVERAGE
(LONG TERM FUEL TRIM) % 0% 0%
RIGHT LTFT AVERAGE
(LONG TERM FUEL TRIM) % 0% 0%
INJECTION PULSE B ANK 1 mS 3.00 - 3.50 mS
INJECTION PULSE B ANK 2 mS 3.00 - 3.50 mS
SPARK ADVANCE DEGREES 0°BTDC 14° B T DC
KNOCK RETARD DEGREES 0° 0°
FUEL TRIM DIAGNOSTIC INHIBIT YES/NO YES YES
TIME FROM START HH:MM:SS VARIES WI TH
ENGINE RUN T IME VARIES WITH ENGINE RUN TIME
TECH 2 SCAN TOOL: FUEL TRIM DATA DESCRIPTIONS
An Explanation f or eac h data mess age dis played on the Tech 2 s c an tool is listed below. T his inf or mation will assis t
in tracking emission or driveability problems, since the displays can be viewed while the vehicle is being driven.
Refer to the Powertrain OBD System Check for additional information.
ENGINE SPEED: Tech 2 Displays a range of 0 to 9999 RPM
The engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired
idle under various engine loads with engine idling.
DESIRED IDLE SPEED: Tech 2 Displays a range of 0 to 3175 RPM
The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the
engine at the desired idle speed.
ENGINE COOLANT TEMPERATURE: Tech 2 Displays a range of -39°C to 140°C (-38°F to 284°F)
The Engine Coolant T emperature (ECT ) Sensor is mounted in the cylinder head of the left bank . The PCM apples
5.0 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature
changes. W hen the sensor is cold ( internal resistanc e high), the PCM monitor s a high signal voltage and interprets
the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases
and the PCM interprets the lower voltage as a warm engine.
IAT: Tech 2 Displays a range of -39°C to 104°C (-38°F to 284°F)
The PCM converts the resistance of the Intake Air Temperature Sensor to degrees. The PCM uses the Intake Air
Temperature (IAT) in order to adjust fuel delivery and spark timing according to incoming air density.
MAP: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.0 volts
The Manifold Absolute Pressure (MAP) Sensor measures the change in the intake manifold pressure from engine
load, and speed changes. As the intake manifold pressure increases, the intake vacuum decreases resulting in a
higher MAP sensor voltage and kPa reading. The PCM uses the MAP sensor signal f or the following: (1) Updating
the BARO reading; (2) Enabling factor for several of the diagnostics.
MAF: Tech 2 Displays a range of 0 to 10,192 Hz
The s ignal that is sent from the Mass Air Flow (MAF) Sensor to the PCM is in the form of a f requency output. This
frequency output changes as the demand of engine air intake changes.
MASS AIR FLOW: Tech 2 Displays a range of 0 to 246 Grams/Sec
The Mass Air Flow (MAF) Sensor measures the change in the intake air flow which results from engine load and
speed changes. As intake air flow increases, the air in the inlet manifold also increases and addition fuel is required.
BARO: Tech 2 Displays a range of 10 to 105 kPa/0.00 to 5.00 Volts
The Barometric Pressure reading is determined from the MAP sensor signal. The PCM monitors the MAP signal
during key up and Wide-Open Throttle (WOT) conditions. The Barometric Pressure compensates for altitude
differences.
TPS ANGLE: Tech 2 Displays a range of 0 to 100%
Computed by the PCM from the TP sensor voltage. The TP angle should read 0% at idle to greater than 80% at
Wide Open Throttle.
TPS VOLTAGE: Tech 2 Displays a range of 0 to 5.10 Volts
Used by the PCM to determine the amount of throttle demanded by the driver. The TPS voltage should read
between 0.25 - 1.25 volts at idle to greater than 4 volts at wide open throttle.
AIR /FUEL RATIO: Tech 2 Displays a range of 0.00 : 99.99
The Air Fuel ratio is determined from the Heated Oxygen sensor output. The PCM uses the fuel trim to adjust
fueling to attempt to maintain an Air Fuel Ratio of 14.7:1. A lower value indicates a richer commanded air fuel
mixture while a higher value indicates a leaner mixture.
FUEL SYSTEM STATUS: Tech 2 Displays “OPEN LOOP” or “CLOSED LOOP”
Closed Loop indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In Open Loop,
the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on TP sensor, engine
coolant, and MAF sensor inputs only.
ENGINE LOAD: Tech 2 Displays a range of 0% to 100%
The PCM c alculates the engine load f r om engine speed and MAF sens or readings . The Engine Load increases with
an increase in RPM or airflow.
LEFT HO2S SENSOR READY (BANK 1) / RIGHT HO2S SENSOR READY (BANK 2): Tech 2 Displays “YES”
or “NO”
Indicates if the HO2S Sensors have reached operating temperature.
LEFT HO2S SENSOR (BANK 1) / RIGHT HO2S SENSOR (BANK 2): Tech 2 Displays a range of 0 to 1000 mV
The HO2S Bank 1 and Bank 2 Sensors parameter represents the fuel control exhaust oxygen sensor output
voltage. The voltage fluctuates constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich
exhaust), while operating in Closed Loop.
LEFT SHORT TERM FUEL TRIM / RIGHT SHORT TERM FUEL TRIM: Tech 2 Displays the Percentage
The Short Term Fuel Trim represents a short-term correction to fuel delivery the PCM makes in response to the
amount of tim e the fuel contr ol oxygen sens or voltage spends above or below the 450 mV thr eshold. If the oxygen
sensor voltage mainly remains less than 450 mV, indicating a lean air/fuel mixture, short term fuel trim
increases into the positive range above 0% and the PCM adds fuel. If the oxygen sensor voltage stays mainly above
the threshold, the short term fuel trim decreases below 0% into the negative range. The PCM reduces the fuel
delivery in order to compensate for the indicated rich condition. Under certain conditions such as an extended idle
and a high ambient temperature, the canister purge may cause the Short Term Fuel Trim to read in the negative
range during normal operation. The Fuel T r im values at max imum author ity may indicate an exces sively rich or lean
system.
LEFT LONG TERM FUEL TRIM / RIGHT LONG TERM FUEL TRIM: Tech 2 Displays the Percentage
The PCM derives the Long Term Fuel Trim from the Short Term Fuel Trim value. The Long Term Fuel Trim
represents a long-term correction of fuel delivery. A value of 0% indicates that the fuel delivery requires no
compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0%
indicates that the fuel system is rich and the PCM is reducing the fuel delivery (decreased injector pulse width). A
positive value significantly greater than 0% indicates that a lean condition exists and the PCM compensates by
adding f uel (increased injector puls e width) . Fuel trim values at m axim um authority indicates an exce ssively rich or
lean system.
FUEL TRIM CELL: Tech 2 Displays a range of 0 to 23
The PCM determ ines fr om MAP and RPM inputs which f uel cell to operate the engine in. A plot of RPM vs MAP is
broken into 24 cells. The fuel trim cell displayed on the scan tool is the cell that the engine is operating under.
FUEL TRIM LEARN: Tech 2 displays “YES” or “NO”
When conditions are appr opriate f or enabling long term f uel trim c orrec tions, the scan tool displays ENABLED. This
indicates that the long term fuel trim is responding to the short term fuel trim. If the scan tool displays DISABLED,
then long term fuel trim will not respond to changes in short term fuel trim.
LEFT SHORT TERM FUEL TRIM AVERAGE / RIGHT SHORT TERM FUEL TRIM AVERAGE: Tech 2 Displays
the Percentage
This parameter indicates the average of the short term fuel trim cells. The short term fuel trim cells are rated
(Weighted) for the amount of which they are us ed. F or ex ample, the PCM rates an idle c ell higher than a wide open
cell. If a f ueling malf unction is occ urring in the idle cell and the wide open cell, the average would be m ore aff ected
by the idle cell. A negative value significantly below 0% indicates that the fuel system is rich and the PCM is
reducing the fuel delivery (decreased injector pulse width). A positive value significantly greater than 0% indicates
that a lean condition exis ts and the PCM is c om pensating by adding fuel (increas ed injector pulse width). When the
average of the cells reaches a predetermined high or low, a fuel trim DTC sets.
LEFT L ONG T ERM FUEL T RIM AVERAGE / RIGHT LONG TERM FUEL T RIM AVERAGE: T ech 2 Displays the
Percentage
This parameter indicates the average of all long term fuel trim cells. The short term fuel trim cells are rated
(Weighted) for the am ount of which they are used. For exam ple, an idle cell is rated higher than a wide open cell. If
a f ueling malf unction occur s in the idle cell and the wide open cell, the average would be more affected by the idle
cell than the wide open cell. A negative value significantly below 0% indicates that a lean condition exists and the
PCM compensates by adding fuel (increased injector pulse width). When the average of the cells reach a
predetermined high or low, a fuel trim DTC sets.
INJECTION PULSE BANK 1 / BANK 2: Tech 2 Displays a range of 0 to 100 m/sec
The Inj ector average indicated the am ount of tim e the PCM com m ands each injector ON during each engine cycle.
A longer injec tor puls e with causes m ore f uel to be delivered. T he Injec tor Pulse Width inc reases with an increased
engine load.
SPARK ADVANCE: Tech 2 Displays a range of -64° to 64°
The scan tool displays the amount of degrees the PCM commands the spark advance on the ignition control (IC)
circuit. The PCM computes the desired spark advance using the following: (1) Engine Coolant Temperature; (2)
Engine Speed (RPM); (3) Load; (4) Vehicle Speed. The PCM adjusts the timing.
KNOCK RETARD: Tech 2 Displays a range of 0.0° to 16°
Knock Retard indicates the am ount of s park the PCM rem oves f rom the IC spark advance in response to the signal
from the Knock Sensor.
FUEL TRIM DIAGNOSTIC INHIBIT: Tech 2 Displays “YES” or “NO”
The s can tool displays No when the PCM determines that certain par am eters pr ohibit the Fuel Trim diagnostic from
running. The scan tool displays Yes when the PCM determines that the Fuel Trim diagnostic is allowed to run.
TIME FROM START: Tech 2 Displays 0:00:00
Indicates the hours, minutes and seconds the engine has been running.
TECH 2 SCAN TOOL: FREEZE FRAME / FAILURE RECORDS DATA DISP LAY
The Tech 2 scan TOOL FREEZE FRAME / FAILURE RECORDS in the table may be used for identification of
conditions at time of DTC set
1. After completing the Powertrain OBD System Check
2. If DTC(s) are set, review Freeze Frame/Failure Records.
IMPORTANT:
Do not use a T ech 2 sc an tool that displays faulty data. Report the condition to the sc an tool manufac turer. The use
of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts. Only the parameters
listed below are used of the VX Series Servic e Inform ation for diagnos ing. If a scan tool dis plays other parameters ,
the values are not recommended by Holden for use in diagnosis.
Test Description The numbers below refer to the circled numbers on the diagnostic table.
1. The scan pos ition refers to the Tec h 2 scan tool FREEZE F RAME / FAILURE RECORDS that will be displayed
in order.
2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a
value that is being sensed or being issued by the PCM.
3. The values shown in the DATA VALUE column indic ates the captur ed data values at the time the DTC was set.
These values are based on KEY ON time and/or ENGINE RUN time and will vary.
TECH 2 SCAN TOOL: FREEZE FRAME / FAILURE RECORDS DATA DISP LAY
SCAN POSITION " UNITS DIS PLAYED # DATA VALUE !
ENGINE SPEED RPM 0 RPM
DESIRED IDLE S PEED RP M 0 RPM
ENG. COOLANT TEMP (ECT) DEGREES C VARIES
START UP ECT DEGREES C VARIES
THROTTLE POSI TI ON 0-100 % 0 %
ENGINE LOAD % %
BARO kPa kPa
BARO SENSOR VOLTS VOLTS VOLTS
MAP SENSOR kPa kPa
MAP SENSOR VOLTS VOLTS VOLTS
MASS AIR FLOW GRAM /SEC GRAM /SEC
FUEL SYSTEM STATUS OPEN LOOP/
CLOSED LOOP OP E N LOOP /
CLOSED LOOP
LEFT SHORT TERM FUEL TRIM
(BANK 1) % +0% to -0%
RIGHT SHORT TERM FUEL TRIM
(BANK 2) % +0% to -0%
LEFT LONG TERM FUEL TRIM
(BANK 1) % +0% to -0%
RIGHT LONG TERM FUEL TRIM
(BANK 2) % +0% to -0%
INJECTION PULSE BANK 1 mS mS
INJECTION PULSE BANK 2 mS mS
AIR FUEL RA TI O % 14.7:1
TRANSMISSION RANGE PARK, REVERSE,
NEUTRAL, DRIVE 4
OD, DRIVE 3 / D,
DRIVE 2, DRIVE 1,
INVALID
PARK, REVE RSE, NE UT RA L, DRIVE 4 OD, DRIVE 3 / D, DRIV E
2, DRIVE 1, INVALID
CURRENT GEAR 1,2,3,4 1,2,3,4
AT Output S peed ( Auto Trans) RPM RPM
TCC BRAKE SWITCH ON / OFF ON / OFF
TCC SOLENOID ON / OFF ON / OFF
TCC PWM ON / OFF ON / OFF
VEHICLE SPEED km/h km /h
TIME FROM START TIME 0:00:00
FIRST ODOMETER km km
LAST ODOMETER km km
FAIL COUNT E R # #
PASS COUNTER # #
NOT RAN COUNTER # #
TECH 2 SCAN TOOL: PIM DATA DISPLAY
IMPORTANT:
Do not use a T ech 2 sc an tool that displays faulty data. Report the condition to the sc an tool manufac turer. The use
of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts. Only the parameters
listed below are used of the VX Series Servic e Inform ation for diagnos ing. If a scan tool dis plays other parameters ,
the values are not recommended by Holden for use in diagnosis.
NOTE:
Only the parameters listed are used in this Section for diagnosis. For more description on the values and use of the
Tech 2 scan tool to diagnosis PIM inputs, refer to the applicable diagnosis table of the VX Series Service
Information. If all values are within the range illustrated, refer to SYMPTOMS Tables in Section 6C3-2B of the VX
Series Service Information.
Test Description: The number(s) below refer to the number(s) on the Tech 2 Scan PIN Data table.
1. T he Tech 2 s can tool F O : PIM DAT A LIST will display scan position's that will be displayed in order. The Tec h 2
scan tool will dis play nine (9) scan pos ition param eters at a tim e. T he down # button will scroll down through all
of the sc an positions one at a tim e. Af ter T IME FR OM ST ART par am eter is displayed, pressing the down arrow
button again will display scan position parameters starting at the top of the list again.
2. UNITS DISPLAYED are the available ways of displaying what each parameter is currently operating in, or a
value that is being sensed or being issued by the PCM.
3. T YPICAL DAT A VALUE is separated into two parts. T hese displayed values are typic al of a norm ally operating
vehicle. The IG NITION ON comparis on should be perform ed first as this may lead to a quick identif ication of a
failure. The ENGINE RUNNING data should be com pared to the IGNITION ON data as a diagnostic check to
make sure the component or system is operating properly.
4. IGNITION ON values are the typical values that should be seen on the Tech 2 scan tool with the ignition ON
and engine stopped. T emperature s ens ors s hould be compared to the ac tual temperatur es by letting the sensor
stabilise overnight and then comparing their values. A difference of 3-5° from the actual temperature may
indicate a problem with the sensor. Use the diagnostic aids table for that sensor to com pare the resistance to
temperature values.
5. ENGINE RUNNING typical data values are an average of display values recorded from normally operating
vehicles at norm ally operating tem perature. T hey are intended to represent what a norm ally functioning system
would typically display.
TECH 2 SCAN TOOL: PIM DATA DISPLAY
TYPI CAL DATA VALUE !
SCAN POSITION " UNITS DISPLAYED # IGNITION ON $ ENGINE RUNNING %
STARTER RELAY OFF/ON OFF OFF
FUEL CONTINUE OFF/ON ON ON
FUEL DISABLE TIME-OUT OFF/ON OFF OFF
FUEL DISABLE CYCLE IGN OFF/ON OFF OFF
AUTO LEARN ACTIVE OFF/ON OFF OFF
PIM THEFT DETERRENT
COMMUNICATION LOST OFF/ON OFF OFF
PASSWORD LEARNING OFF/ON OFF OFF
PIM DTC STATUS NO DTC
DTCs SET NO DTC NO DT C
SOFTWARE VERSION FOUR DIGIT NUMBER
(VARIES WITH PCM
SOFTW ARE
UPDATES)
5.5 5.5
PIM COMMUNICATION DISABLE OFF/ON OFF OFF
A/C CLUTCH OFF/ON OFF OFF
CHECK POWERTRAIN
(CPL) OFF/ON ON OFF
LOW COOLANT LEVE L YES/NO NO NO
OIL PRESS URE SENSOR OFF/ON OFF ON
ENGINE OIL CHANGE OKAY / SERVICE
REQUESTED OKAY OKAY
ENGINE OIL LIFE RESET OFF/ON OFF OFF
SHIFT PATTE RN E CONOMY / P OWER ECONOMY ECONOMY
LOW SPEED FAN REQUEST OFF/ON OFF OFF
LOW SPE ED FAN RUN ON YES/NO NO NO
TECH 2 SCAN TOOL: PIM DATA DISPLAY DESCRIPTIONS
A list of ex planations for each data m essage disp layed on the Tec h 2 scan tool begins as f ollows . T his inform ation
will assist in tracking em ission or driveability problems, since the displays can be viewed while the vehicle is being
driven. Refer to Powertrain OBD System Check for additional information.
START RELAY: Tech 2 Displays "OFF" or "ON"
The scan tool displays ON when the Start Relay is enabled.
FUEL CONTINUE: Tech 2 Displays "OFF" or "ON"
Tech 2 displays ON if the proper Theft Deterrent signal is sent from the PIM to the PCM for fuel control.
FUEL DISABLE TIME-OUT: Tech 2 Displays "OFF" or "ON"
Tech 2 displays ON when the PCM sends a message back to the PIM indicating PCM is satisfied with Theft
Deterrent signal and is allowing fuel injection.
FUEL DISABLE CYCLE IGN: Tech 2 Displays "OFF" or "ON"
Tec h 2 displays OFF when the PCM security has failed. Engine will not be fueled until the ignition has been c ycled
from ON to OFF to ON.
AUTO LEA RN ACTIVE: Tech 2 Displays "YES" or "NO"
Tech 2 displays YES if the PCM is in automatic password learning mode.
PIM THEFT DETERRENT COMMUNICATION LOST: Tech 2 Displays "YES" or "NO"
Tech 2 indicates YES if there is a Theft Deterrent communication loss between the PIM and PCM.
PASSWORD LEARNING: Tech 2 Displays "YES" or "NO"
Tech 2 displays YES if the PIM is in a current Password Learn mode. PCM will learn CLASS II security code from
PIM on the next ignition cycle.
PCM DTC STATUS: Tech 2 Displays “NO DTCs” or “DTCs SET”
Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.
PIM DTCs STATUS: Tech 2 Displays “NO DTCs” or “DTCs SET”
Indicates if a DTC is set. This does not indicate what DTC is set, just informs that DTC (s) are or are not set.
SOFTWARE VERSION: Tech 2 Displays Number of Software ID in PCM.
PIM COMMUNICATION DISABLE - Tech 2 Displays "ON" or "OFF"
A/C CLUTCH: Tech 2 Displays "ON" or "OFF"
Represents the commanded state of the A/C clutch control relay. Clutch should be engaged when ON is displayed.
CHECK POWERTRAIN LAMP (CPL) or MALFUNCTION INDICATOR LAMP (MIL): Tech 2 Displays "OFF" or
"ON"
Indicated if the instrument panel (CPL) is ON or OFF.
LOW COOLANT LEVEL: Tech 2 Displays "NO" or "YES"
This is an indication to the PC M that the coolant level is low. If the c oolant level is low, the PCM will turn on the Low
Coolant Lamp.
OIL PRESSURE SENSOR: Tech 2 Displays "OFF" or "ON"
This is an indication to the PCM if the oil press ure is low. If the oil pres sure is low, the PCM will turn ON a Low Oil
Warning Lamp.
ENGINE OIL CHANGE: The Tech 2 Displays “OKAY” or “SERVICE REQUESTED”
The scan tool will display the status of the engine oil change condition.
ENGINE OIL LIFE RESET: Tech 2 Displays "OFF" or "ON"
The scan tool will display ON when the SERVICE REQUESTED is indicated on the instrument panel. The reset
function can be performed at the instrument panel trip computer.
SHIFT PATTERN: Tech 2 Displays “ECONOMY” or “POWER”
This display shows the state of the POWER/ECONOMY switch.
LOW SPEED FAN REQUEST: Tech 2 Displays "ON" or "OFF”
Indicates if the engine cooling fan low speed relay has been commanded ON or OFF.
LOW FAN RUN ON: Tech 2 Displays "NO" or "YES"
The scan tool will indicate NO if the PCM is commanding the BCM to enable the Low Fan Relay when the key is
turned OFF.
TECH 2 SCAN TOOL: AUTOMATIC TRANSMISSION DATA
Use the scan tool data values under the following conditions:
• The Powertrain On-Board Diagnostic (OBD) System Check is complete.
• The on-board diagnostics are functioning properly.
• No DTCs are present.
The following values represent a typical display recorded from a properly functioning system.
IMPORTANT:
Do not use a T ech 2 sc an tool that displays faulty data. Report the condition to the sc an tool manufac turer. The use
of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts. Only the parameters
listed below are used of the VX Series Servic e Inform ation for diagnos ing. If a scan tool dis plays other parameters ,
the values are not recommended by Holden for use in diagnosis.
The following scan tool values below were recorded under the following conditions:
• Engine at Idle
• Upper radiator hose hot
• Closed throttle
• Transmission in PARK
• Closed Loop operation
• Accessories OFF
• Brake pedal not applied
TECH 2 SCAN TOOL: AUTOMATIC TRANSMISSION DATA
SCAN TOOL PARAMETER DATA LIS T* UNITS TYP ICAL DATA VAL U E
1-2 Shift Ti me F0, F1 Seconds Varies
1-2 Solenoid A F0, F1 On/Off On
1-2 TAP Cell (4-16) F1 kP a/PSI Varies
2-3 Shift Ti me F0, F2 Seconds Varies
2-3 Solenoid B F0, F1, F2 On/Off On
2-3 TAP Cell (4-16) F2 kP a/PSI Varies
3-2 Downshift Solenoi d F0 On/Off On
3-4 Shift Ti me F0 Seconds Varies
A/C Clut ch (Air Condit ioni ng) F0 On/O ff Off
Adapt Shi f t Status F0, F1, F2 Enabled/Dis abl ed Disabled
AT Output S peed (Autom at i c Transm i ssion) F0 RPM 0
Battery Voltage F0 Volts 12-14 Volt s
Commanded Gear F0, F1, F2 1, 2, 3, 4 1
Current TAP Cell F1, F2 4-16 Varies
Current TAP Memory F1, F2 -16 t o +16 Varies
DTC Status - No DTC/DTC Set No DTC
Engine Coolant Temperature F0 ° C Varies
Engine Speed F0 RP M Varies (640-680)
Engine Torque F0 N.M Varies
Intake Air Temperature F0 ° C Varies
Latest Shift F0 Seconds Varies
Actual P CS (P ressure Control Solenoid) F0 Milliamps Varies
(1055-1074 Milliamps)
Commanded PCS (Pres sure Control Solenoid) F0 Milliamps Varies
(1055-1074 Milliamps)
PCS Duty Cyc l e (Pressure Cont rol Solenoid) F0 Perc ent Varies (62-64%)
Shift Pattern F0 Power/Economy/Cruise Economy
Speed Ratio F0 Rat i o 8.00:1
TCC Brake Switch (Torque Converter Clutch) F0 Open/Closed Closed
TCC PWM (Torque Converter Clut ch) F0 Percent 0%
TCC Solenoid (Torque Converter Cl utch) F0 On/Off Of f
TCC Mode F0 0-5 0
TCC Slip Speed (Torque Converter Clutch) F0 RPM +/- 50 RP M
from Engine Speed
TFP Switch A/B/C F0 Open 12 V /Closed 0 V Open 12 V/ Clos ed 0
V/Open 12 V
TFT Sensor (Transmi ssion Fluid Tem perature) F0 Volts Varies
Throttle Position F0, F1, F2 Percent 0%
Throttle P osition Sensor F0 Volts 0.49-0. 55 V
Time From Start F0 Hr/ Min/ Sec Varies
Transm i s sion Fluid Temperature F0 ° C Varies
Transm ission Hot Mode F0 On/Off Of f
Transm i s sion Range (TR) F0 Park/ Neut ral , Reverse,
Park/ Neut ral , Drive 4
O/D, Drive 3/ D, Drive 2,
Drive 1
Park/Neutral
TR Switch A (Transmission Range) F0 Open 12 V/Closed 0 V Closed 0 V
TR Switch B (Trans mis sion Range) F0 Open 12 V/Closed 0 V Open 12 V
TR Switch C (Transmission Range) F0 Open 12 V/Closed 0 V Open 12 V
TR Switch P (Transmission Range) F0 Open 12 V/Closed 0 V Closed 0 V
Vehicle Speed F0 k m/h 0
*Data List Legend
• F0: Transmiss i on Dat a
• F1: 1-2 Adapt Data
• F2: 2-3 Adapt Data
TECH 2 SCAN TOOL: AUTOMATIC TRANSMISSION DATA DISPLAY DESCRIPTIONS
1-2 SHIFT TIME
Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 1-2 shift. The shift time is based
on the engine RPM drop after the commanded 1-2 shift. This value is only accurate if the shift was adaptable.
1-2 SOLENOID A
Displays ON or OFF. This parameter is the commanded state of the 1-2 shift solenoid valve. ON represents a
commanded energised state (current is flowing through the solenoid). OFF represents a non-commanded state
(current is not flowing through the solenoid).
1-2 TAP CELL (4-16)
Displays kPa. T his par ameter dis plays the amount of pr es s ure var ied f rom a c alibrated bas e line pr ess ur e for shif ts .
Each T AP Cell is based on a c alibr ated s hif t tor que value. Each TAP Cell value is c alc ulated fr om the last shift time.
This cell pressure is used in addition to the calibrated base line pressure to adjust the application of a clutch or band
during the next shift.
2-3 SHIFT TIME
Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 2-3 shift. The shift time is based
on the engine RPM drop after the commanded 2-3 shift. This value is only accurate if the shift was adaptable.
2-3 SOLENOID B
Displays ON or OFF. This parameter is the commanded state of the 2-3 shift solenoid valve. ON represents a
commanded energised state (current is flowing through the solenoid). OFF represents a non-commanded state
(current is not flowing through the solenoid).
2-3 TAP CELL (4-16)
See 1-2 Tap Cell (4-16)
3-2 DOWNSHIFT SOLENOID
Displays ON or OF F. T his param eter indic ates if the 3- 2 shift solenoid valve as sem bly is currently comm anded ON
or O FF. The solenoid com m anded state is based on the transmiss ion tem perature. T he solenoid will change s tates
during a 3-2 downshift to regulate the appropriate pressure. The commanded state of the solenoid occurs at
approximately 48 km/h with a throttle increase.
3-4 SHIFT TIME
Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 3-4 shift. The shift time is based
on the engine RPM drop after the commanded 3-4 shift. This value is only accurate if the shift was adaptable.
A/C CLUTCH
Displays ON or OFF. This param eter indic ates the com manded s tate of the A/C contr ol relay. The clutc h should be
engaged when ON displays.
ADAPT SHIFT STATUS
Displays ENABLED or DISABLED. ENABLED indicates that the proper operating conditions were all within the
proper operating range during the last shif t and that the shift tim e was accurate. This shift infor mation is then used
through the adaptive function in order to update the adapt cells. DISABLED indicates that not all of the operating
conditions were met in order to enable this function and that the adapt cells were not updated.
AT OUTPUT SPEED (AUTOMATIC TRANSMISSION)
Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the transmission output shaft
expressed as revolutions per minute.
BATTERY VOLTAGE
Displays a range of 0.0-25.5 V. This represents the system voltage measured by the PCM at its ignition feed.
COMMANDED GEAR
Displays 1, 2, 3 or 4. This parameter indicates the current commanded state of the shift solenoids.
CURRENT TAP (TRANSMISSION ADAPTIVE PRESSURE) CELL
Displays a TP cell range of 0-16. This parameter indicates the current throttle position cell used for line pressure
modification (adaptation).
CURRENT TAP
(TRANSMISSION ADAPTIVE PRESSURE) MEMORY
Displays a range of - 16 to +16 psi. This parameter is the am ount of press ure that is added to base line pres sure to
adjust the holding effort of a clutch or band, while shifting.
ENGINE COOLANT TEMPERATURE
Displays a range of - 40°C to 151° C. This param eter is the input signal of the Engine Coolant T em perature Sensor
(ECT) . The engine coolant temperature is high ( 151° C) when the signal voltage is low (0 V), and the engine c oolant
temperature is low (-40°C) when the signal voltage is high (5 V).
ENGINE SPEED
Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the engine expressed as
revolutions per minute.
ENGINE TORQUE
Displays a range of 0-9999 N.m. This parameter indicates the amount of torque that is delivered from the engine.
INTAKE AIR TEMPERATURE
Displays a range of -40°C to 215°C. The IAT Sensor is a therm istor that is used to monitor the temperature of the
air enter ing the intake m anif old. T he PCM applies 5 volts to the sensor on a 5 volt refer ence cir cuit. When the air is
cool, the resistanc e in the sensor will be high. If the air is warm, the sens or resis tance will be low and the PCM will
sense a low voltage signal. The PCM converts the signal of the IAT sensor to degrees Celsius. Intake Air
Temperature is used by the PCM to adjust fuel delivery and spark timing.
LATEST SHIFT
Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last upshift. This value is only
accurate if the shift was adaptable.
ACTUAL PCS (PRESSURE CONTROL SOLENOID)
Displays a range of 0.00-1.10 amps. T his parameter is the actual current of the pressure contr ol solenoid circuit at
the control module. Zero amp (no current flow) indicates actual higher line pressure. Actual lower line pressure is
indicated by 1.1 amps (high current flow).
COMMANDED PCS (PRESSURE CONTROL SOLENOID)
Displays a range of 000-1100 Milliam ps . This param eter is the com m anded c urrent of the pressur e control solenoid
circuit. Zero Milliamps (no current flow) indicates commanded higher line pressure. Commanded lower line pressure
is indicated by 1100 Milliamps (high current flow).
PCS DUTY CYCLE (PRESSURE CONTROL SOLENOID)
Displays a range of 0- 100%. T h is par ameter is the commanded state of the press ur e contr ol s olenoid expr es sed as
a percent of energised ON time. Zero percent indicates zero ON time (non-energized) or no current flow.
Approximately 60% at idle indicates maximum ON time (energized) or high current flow.
SHIFT PATTERN
Displays ECONOMY, POWER, CRUISE. This parameter indicates the shift pattern that is currently being used.
Through electronic oper ation, the PCM can change the shift patter n for ECONOMY (norm al driving), POW ER ( late
upshift points, reduc ed shift times , TCC apply in third and fourth), and CRUISE (earlier downshifts and later upshift
points).
SPEED RATIO
Displays a range of 0.00:1 to 8.00:1. T his parameter indic ates engine speed divided by tr ansmiss ion output speed.
This value is used to estimate transmission gear ratio.
TCC BRAKE SWITCH
Displays OPEN or CLOSED. T his parameter indicates the state of the br ake switch circ uit input. OPEN indicates a
zero voltage input (brake switch open, brake pedal applied). CLOSED indicates a B+ voltage input (brake switch
closed, brake pedal released).
TCC PWM
Displays a range of 0- 100%. This param eter is the comm anded perc entage of ON tim e of the T CC PW M s olenoid.
Approxim ately 90 percent r epresents an ON (ener gized) c omm anded state. Zero percent repr esents an O FF (non-
energized) commanded state. This commanded state is applied at a vehicle speed between approximately 0-16
km/h.
TCC SOLENOID
Displays ON or OFF. This parameter is the commanded state of the TCC solenoid. ON indicates a commanded
energized state (curr ent is flowing through the solenoid). OFF indicates a c omm anded non-energized state (current
is not flowing through the solenoid). This commanded state occurs at various vehicle speeds between applications.
TCC MODE
Displays a range of 0 through to 5. Zero (0) or OFF Mode indicates that the PCM commands the TCC OFF at a
calibrated minimum throttle. The calibrated minimum throttle is different at low vehicle speeds than it is at high
vehicle speeds.
OFF Mode is also active when the transm ission is in the wrong gear range, the engine or the transmission is cold,
the brake input indicates that the brakes are ON, a downshift or upshift is initiated, the engine is at idle, the
transmission is in HOT Mode or a misfire is detected. One (1) or RELEASE Mode indicates that the PCM
commands the release of the TCC. Two (2) or Apply Mode indicates that the PCM commands the apply of the TCC.
Application pressure varies based on normal or performance operations, hot conditions or if the cruise control is
active. APPLY Mode is used under normal driving conditions. All apply pressure is dependent on throttle position
and vehicle speed.
Three (3) or APPLY ENABLE Mode indicates that enabling conditions are met for applying the TCC (enabling
conditions include vehic le speed, gear s election, tr ans mission temperatur e, throttle angle, br ake switch status, etc.).
Four ( 4) or LOCKED Mode indicates that the PCM comm ands full capac ity of the T CC when the transmiss ion is in
fourth gear and the vehicle speed is greater than a calibrated value.
When variable TCC apply pressure stops (APPLY Mode), maximum TCC pressure is used. Five (5) or COAST
Mode indicates that the PCM com mands apply of the TCC when the transmission is in fourth gear and the throttle
and vehicle speed are not high enough to enable APPLY Mode, but high enough to keep the TCC applied. W hen
COAST Mode is active, TCC apply pressure is set to a predetermined amount.
TCC SLIP SPEED (TORQUE CONVERTER CLUTCH)
Displays a range of -4080 to 4079 RPM. This parameter is the difference between transmission output speed and
engine speed. A negative value indicates that the engine speed is less than the output speed (deceleration).
A positive value indicates that the engine speed is greater than the output speed (acceleration). A value of zero
indicates that the engine speed is equal to the output speed (TCC applied).
TFT SENSOR (TRANSMISSION FLUID TEMPERATURE)
Displays a range of 0.00- 5.00 V. When the tr ansmiss ion f luid is cold, the s ens or r es istanc e is high and the PCM will
sense high signal voltage. As the transmission fluid temperature warms to a normal operating temperature, the
sensor resistance becomes less and the voltage decreases.
TFP SWITCH A/B/C
Displays Open 12 V/Closed 0 V, Open 12 V/Closed 0 V, Open 12 V/Closed 0 V. These parameters are the three
inputs fr om the Autom atic T rans m ission Fluid Pr essur e Manual Valve Position Switch Assem bly. Closed represents
a 0 voltage signal. Open represents a B+ voltage signal.
THROTTLE POSITION
Displays a range of 0-100%. The TP angle is computed by the PCM from the TP Sensor voltage. The TP angle
should read 0% at idle and 100% at Wide Open Throttle (WOT).
THROTTLE POSITION SENSOR
Displays a range of 0.00-5.00 volts. The TP Sensor is used by the PCM to determine the amount of throttle
demanded by the driver. Voltage is below 1 volt at idle and above 4 volts at Wide Open Throttle (WOT).
TIME FROM START
Displays a range of 0:00:00 to 18:12:15 hr/min/sec. This parameter measures how long the engine has been
operating. When the ignition switch is turned OFF, the value is reset to zero.
TRANSMISSION FLUID TEMPERATURE
Displays a range of -40°C to 151°C. T his param eter is the input signal of the transmis sion fluid temper ature sensor.
Trans m ission fluid tem perature is high ( 151°C) when signal voltage is low (0 V), and trans m ission f luid tem perature
is low (-40°C) when signal voltage is high (5 Volts).
TRANSMISSION HOT MODE
Displays ON or OFF. This parameter monitors transmission temperature. ON indicates that the transmission
temperature has exceeded 135°C.
TRANSMISSION RANGE (TR)
Displays PARK / NEUTRAL, REVERSE, PARK/NEUTRAL, DRIVE 4 O/D, DRIVE 3/D, DRIVE 2, DRIVE 1. The
scan tool displays the decoded pos ition of the trans m ission Park /Neutral range switch (PRNDL). T his inf orm ation is
then sent to the instrument panel and is displayed to the operator.
TR SWITCH A (TRANSMISSION RANGE)
Displays OPEN 12 V/CLOSED 0 V. This param eter is the input from the automatic transm iss ion Park/Neutral range
switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.
TR SWITCH B (TRANSMISSION RANGE)
Displays OPEN 12 V/CLOSED 0 V. This parameter is the input from the automatic transmission PARK/NEUTRAL
range switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.
TR SWITCH C (TRANSMISSION RANGE)
Displays OPEN 12 V/CLOSED 0 V. This param eter is the input from the automatic transm iss ion Park/Neutral range
switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.
TR SWITCH P (TRANSMISSION RANGE)
Displays OPEN 12 V/CLOSED 0 V. This parameter is the input from the automatic transmission PARK/NEUTRAL
range switch. OPEN represents a B+ voltage signal and CLOSED represents a 0 voltage signal.
VEHICLE SPEED
Displays a range of 0-255 km/h. This parameter is the input signal from the vehicle speed sensor assembly.
DIAGNOSTIC TABLES
INTRODUCTION
The diagnostic tables are designed to provide fast and efficient means of fault location for all engine and
transmission f unc tions as s oc iated with the PCM. Each diagnostic table us es 2 pages; a table on the right side page,
and a facing page on the left side page. The left side "facing page" contains pertinent information, including
Diagnostic Trouble Code setting parameters and circuit diagrams. The table steps are explained by the
corresponding numbered paragraph on the left side facing page.
When diagnosing any problem, always begin with the ON-BOARD DIAGNOSTIC SYSTEM CHECK This will lead
you to the other tables. DO NOT GO DIRECTLY TO A SPECIFIC TABLE or false diagnosis and replacement of
serviceable parts could result. After a fault is corrected and all DTCs have been cleared, repeat the ON-BOARD
DIAGNOSTIC SYSTEM CHECK to assure that the proper repairs have been made.
The "A" Table pages and the Diagnos tic Trouble Code diagnostic s pages are constr ucted in a similar fashion. The
box at the top of the left page contains a wiring diagram showing the components involved in each circuit.
Immediately below the box is a brief circuit description. On the facing right-hand page a troubleshooting table for
diagnosing c onditions. Step numbers on the r ight-hand page nex t to the action box es in the table relate to the items
in the Test Decription on the left-hand page. These items provide an explanation of each test in the table.
The appropriate step in any of the trouble shooting tables will instruct you either to make a specific repair or to
continue diagnosis. If further diagnosis is needed, the step will specify where to continue.
The Yes or No column in any diagnostic table will instruct you either to make a specific repair or to continue
diagnosis. If further diagnosis is needed, the Yes or No column will specify where to continue.
If the condition is intermittent, the trouble shooting table will direct you to the diagnostic aids on the facing page.
This section gives suggestions for diagnosing intermittent conditions and explains how some faults can occur.
Remember, tables are for solving active conditions or Diagnostic Trouble Codes, not intermittent conditions. Use
symptom diagnosis for solving intermittent conditions.
Figure 6C3-2-9 Diagnostic Flow Table Typical
WRITING THE REPAIR ORDER
The repair order is one of the most important tools
a technician can have. Like his other tools, the
repair order must be highly accurate to give him the
greatest help.
It's up to the service adviser to supply the
technician with this highly accurate tool. Problems
begin for the technician when the repair order is
incomplete or is incorrect.
An incomplete repair order doesn't provide the
technician with a good starting point for the
diagnosis. Consequently, the tec hnician may was te
time, using a “ shotgun” approach attem pting to find
the problem.
An incorrectly written repair order can lead the
technician down the wrong diagnostic path,
preventing him from finding the problem.
Consequently, a service adviser needs to write an
accurate and complete repair order. This is
accom plished by asking the driver these questions:
WHO? WHAT? WHEN? WHERE? and HOW?
Figure 6C3-2-10 An Incomplete Repair Order
"WHO"? QUESTIONS
"WHO"? is the first question you need to ask. As
you begin to fill out the repair order, you need to
find out who was driving the vehicle when the
problem occurred and talk directly to that person if
at all possible.
This allows you to give first-hand inf or mation on the
problem to the technician, which is critical to
diagnosing the problem. If you can't talk directly to
this person, get their name and phone number so
the technician can call the driver if needed.
"WHAT"? QUESTIONS
The next step is to find out "WHAT"? the problem
is. If it's a driveability problem, and it seems to be
complex, bring the technician who's going to work
on the vehicle into the picture if at all possible.
Allow the technician to question the driver directly,
so he can get the inf orm ation he needs to help him
diagnose the problem. Again, this is so he can get
first-hand knowledge of the problem.
If you don't involve the technician with the driver,
you need to ask if the Check Powertrain Lamp
(CPL) is ON all the time, coming ON and OFF
during the same key cycle, or is never ON.
Figure 6C3-2-11 Typical Symptomatic Diagnostic Table
This is important to the technician because this
informs him which diagnostic direction to take.
These tables are different from one another. If a
technician is f ollowing the wrong table, a lot of time
is wasted. So, ask the driver questions about the
Check Powertrain Lamp (CPL).
Other good "WHAT"? questions are. Under what
conditions did the problem occur?
Were they accelerating, decelerating, or coasting?
Were they driving in the city or on the freeway?
What were the environmental conditions? Was it
raining? snowing? hot? cold? The technician may
need to duplicate these conditions as closely as
possible if he is to find the cause of the problem.
"WHEN"? QUESTIONS
"WHEN"? questions are the next step. If the driver
says the Check Powertrain Lamp (CPL) was ON,
you need to ask when the Check Powertrain Lamp
(CPL) came ON and how long it has been ON. Is
the Check Powertrain Lamp (CPL) ON before or
during starting, or when the engine is running?
More im portant, you need to ask when the problem
first oc curred. Maybe it began af ter the vehicle was
serviced f or a related pr oblem or for som ething that
appears to be totally unrelated.
The technician also needs to know if the problem
has become worse. This information may give the
technician som e clues as to what the problem may
be.
"WHERE"? QUESTIONS
"WHERE"? is the next question. The location
where the problem occurs may give the technician
an idea as to what may be contributing to the
problem, such as electromagnetic interference
from overhead power lines.
"HOW"? QUESTIONS
To round out your questioning, you need to ask the
driver "HOW "? often the problem occurs. This can
give the technician direction as to what type of
system may be causing the problem: electrical,
mechanical, vacuum, etc.
Figure 6C3-2-12 Typical Diagnostic Table
SUMMARY
In summary, you need to obtain the following
information from the driver:
• Who the principal driver is.
• What the problem is.
• When the problem began.
• Where the problem occurs.
• How often the problem occurs.
Complete answers to these questions will aid the
technician in diagnosing the problem.
VERIFYING THE COMPLAINT
ENGINE COMPARTMENT INSPECTION
The most important step in diagnosing a driveability complaint is to verify the complaint. This means you have to
duplicate the problem if possible.
Start by performing an engine compartment inspection. Check the integrity of all the electrical connections and
vacuum hoses, etc. Also, check the wire routing for the possibility of Electromagnetic Interference (EMI).
CHECKING FOR STORED DIAGNOSTIC TROUBLE CODES
As you check for Diagnostic Trouble Codes, keep in mind that intermittent faults may not store a Diagnostic
Trouble Code. So proceed with verifying the complaint, even if no diagnostic trouble codes are stored.
If a diagnostic trouble code is stored, check the service bulletins for the particular vehicle you're working on.
ROAD TESTING THE VEHICLE
This step is optional if the repair order states.
• The driveability problem is intermittent.
• You did not find any problems under the bonnet .
• No Diagnostic Trouble Codes are stored.
Then you need to road test the vehicle in order to recreate the problem.
This is an important step because the problem has to be present in order to repair the problem.
Most intermittent driveability problems are repeatable. That is what road testing is all about.
Before you go on your road test, review the vehicle's s ervice his tory. This inf orm ation can give you clues as to what
may be causing the driveability problem and what you need to watch.
Read the repair order and think about what systems could possibly cause the problem. This is essential to finding
the problem. Think about how the system or systems in question works, what inputs are needed and what could
cause the problem.
Check all the inputs required f or a circuit, whether the circuit actually has trouble or if you only suspect trouble. All
inputs are needed and m ust be within a "normal" r ange. You will want to pay attention to these system s and circuits
during and after the road test.
As you're road testing, put the Tec h 2 sc an tool in the s napshot mode s o you can capture the system data when the
problem occurs.
Do not discount the other information the Tech 2 snapshot mode can supply you with.
DON'T FORGET THE BASICS
Whether or not you find anything wrong during the road test, don't forget the basics.
Electrical connections such as power feeds and earths are vital to the operation of almost all of the vehicle systems.
No matter how good the system is, it is still working in combination with the engine. If the engine is not in good
condition, the computer system can't make up for the condition.
Compare performance problems, such as lack of power, with a comparable vehicle. This will let you know if the
driver complaint really is a problem or something that is normal.
If you can't repeat the problem, and you need more information for diagnosing, call the driver who was driving the
vehicle when the problem occurred. This type of professionalism will probably help you diagnose the problem.
EEPROM
If a vehicle is just starting to have an intermittent driveability problem and it has accumulated more than 30,000
kilometres, chances are that the EEPROM calibration is not at fault.
If the vehicle was r unning proper ly for suc h a long time, the original EEPROM c alibr ations are not the problem since
the EEPROM calibrations don't change, the chances of the EEPROM going bad are rare. T here may, however, be
an updated EEPROM calibration for a particular condition, so check service bulletins for calibrations updates.