Test C: The Temperature Gauge Is Inoperative

PINPOINT TEST C: THE TEMPERATURE GAUGE IS INOPERATIVE

C1-C4:

Normal Operation
The PCM receives the engine coolant temperature status through hardwired circuitry to the cylinder head temperature (CHT) sensor. The instrument cluster receives the engine coolant temperature data from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster monitors the engine coolant temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

If the instrument cluster does not receive the engine coolant temperature status message from the PCM for 5 seconds or less, the instrument cluster defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the instrument cluster does not receive the engine coolant temperature status message from the PCM for more than 5 seconds or if the data received is deemed invalid, the instrument cluster sets DTC U0100 in continuous memory and defaults the temperature gauge to cold (C).

NOTE: If DTC U0100 is set in the instrument cluster, other observable symptoms may be an inoperative speedometer, tachometer or odometer.

Possible Causes
- Instrument cluster