Gauge temp sensor location 2002 VX Commodore

[james32423]

Hello all.
Trying to locate the temp sensor for the temp gauge which keeps jumping to max and giving spurious high temp alarms. Already managed to find the temp sensor for the PCM which is located on the thermostat housing (see photo attached). Have removed and tested this sensor - shorted it out to simulate high coolant temp and it does exactly what it should (brings on radiator fan and ECU light comes on). BUT there is no change in the the temp gauge and no high temp alarm.
There must be a separate temp sensor somewhere for the gauge? The service manual does mention this but have gone over the whole engine and cannot find it anywhere.

Anyone got any ideas about this?

Cheers

 

[lout]

i believe vx only has 1 sensor
VR VS had 2

 

[Immortality]

Only the one sensor on the VX, sensor sends a signal to the PCM which supplies the temp to the dash via the canbus system.

 

[BlackVXGTS]

VT/VX uses Bus Master (where the BCM is the Master) to provide Serial Data (such as instrument data) not CanBus, but the process is similar.

Have you checked to see if any error codes have been set? Refer to the attached for coolant temperature sensor operation:

 

[james32423]

Only the one sensor on the VX, sensor sends a signal to the PCM which supplies the temp to the dash via the canbus system.

Ok, cheers for confirming.
That makes it a bit more difficult to fault find.

Strange that shorting the coolant temp sensor doesn't make the temp gauge go high while it still turns on the radiator fan (with the engine running).
Any idea if the PCM needs to see another signals from elsewhere in addition to the high temp signal from the coolant temp sensor in order for it to give an output to the temp gauge to go high?

With the way the temp gauge shoots up randomly from normal range to max every now and then, hopefully it is just a wiring issue local to the gauge.

 

[james32423]

VT/VX uses Bus Master (where the BCM is the Master) to provide Serial Data (such as instrument data) not CanBus, but the process is similar.

Have you checked to see if any error codes have been set? Refer to the attached for coolant temperature sensor operation:

Great info. Much appreciated.