SECTION 6C1 - POWERTRAIN MANAGEMENT –

V6 ENGINE

CAUTION:

This vehicle will be equipped with a Supplemental Restraint System (SRS). A SRS will consist of either

seat belt pre-tensioners and a driver's air bag, seat belt pre-tensioners and a driver's and front

passenger's air bag s or seat belt pre- tensio ners, d riv er’s and fron t p asseng er’s air bag and lef t and rig ht

hand side air bags. Refer to SAFETY PRECAUTIONS, Section 12M Supplemental Restraint System of the

VT Series I Service Information before performing any service operation on, or around any SRS

components, the steering mechanism or wiring. Failure to follow the SAFETY PRECAUTIONS could

result in SRS deployment, resulting in possible personal injury or unnecessary SRS system repairs.

CAUTION:

This vehicle may be equipped with LPG (Liquefied Petroleum Gas). In the interests of safety, the LPG

fuel system should be isolated by turning 'OFF' the manual service valve and then draining the LPG

service lines, before any service work is carried out on the vehicle. Refer to the LPG leaflet included with

the Owner's Handbook for details or the appropriate Section of this Service Information CD for more

specific servicing information.

1. GENERAL INFORMATION

The V6 engine powertrain m anagement system used on VT Series II Models carries over from VT Series Models,

noting the following:

As a running change to all VT Series Models, the crank sensing input to the Powertr ain Control Module (PCM) was

no longer required (engine backfire is prevented by the Direct Ignition System (DIS) module) and as such deleted.

W hile this change does not ef fect the information published in Section 6C1 POWERTRAIN MANAGEMENT – V6

ENGINE of the VT Series I Service Inform ation, it is recom mended that when diagnosing a system f ault, reference

to the latest VT Series wiring diagrams are used.

Provision for a remote connection to a tachometer was previously provided via circuit 121 at connector YE5. As

TECH 2 is capable of reading the engine RPM, the provision for remote access to the RPM signal was deemed

unneccessary, and as such connector YE5 was deleted.

With the introduction of revised engine cooling fans for the V6 engine comes a revision to the cooling fan control

logic (ON/OFF):

The low speed engine cooling fan relay will be turned ON when:

•Air conditioning request indicated (YES) and the vehicle speed is less than 30 km/h or

•Air conditioning pressure is greater than 1500 kPa or

•Coolant temperature is greater than 104°C or

•An engine coolant temperature sensor failure is detected by the PCM, refer to Section 6C1 POWERTRAIN

MANAGEMENT - V6 ENGINE of the VT Series I Service Information for additional information.

•When the ignition switch is turned from ON to OFF and the engine coolant temperature is above 117°C. The

BCM will continue to energise the low speed engine cooling fan micro relay for approximately four minutes.

The PCM will request the BCM to switch off the low speed engine cooling fan relay when the following conditions

have been met:

•Air conditioning request not indicated (NO) and the coolant temperature is less than 99°C or

•Air conditioning reques t indicated (YES) with pressure les s than 1170 kPa, vehic le speed gr eater than 50 km /h

and coolant temperature less than 99°C.

Techline

The PCM determines when to enable the high speed engine cooling fan relay based on inputs from the ECT

sensor. The high speed engine cooling fan relay will be turned ON if the low speed engine cooling fan relay has

been energised for one second and the following conditions have been met:

•If there is a BCM message response fault, setting a DTC 92 or

•An engine coolant temperature sensor failure is detected by the PCM, refer to Section 6C1 POWERTRAIN

MANAGEMENT - V6 ENGINE of the VT Series I Service Information for additional information or

•Engine coolant temperature is above 107°C or

•Air conditioning pressure is greater than 2000 kPa.

NOTE: If the low speed engine cooling fan is of f when the criteria for turning the high speed engine cooling fan on

are first met, the high speed engine cooling fan will turn on for five seconds after the low speed engine cooling fan is

switched on.

If both the high and low speed engine cooling fans ar e enabled, the PCM will turn the high speed engine c ooling f an

off when:

•The engine coolant temperature is less than 103°C and

•Air conditioning request is not indicated (No) or

•Air conditioning request is indicated (Yes) and the pressure is less than 1500 kPa.