Pinpoint Test D: The Temperature Gauge Is Inoperative

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test D: The Temperature Gauge Is Inoperative

Normal Operation

The PCM receives the engine temperature status through hardwired circuitry to the Cylinder Head Temperature (CHT) sensor. The Instrument Cluster (IC) receives the engine temperature data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IC monitors the engine temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

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

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

This pinpoint test is intended to diagnose the following:

- PCM
- IC



PINPOINT TEST D: THE TEMPERATURE GAUGE IS INOPERATIVE

-------------------------------------------------
D1 CARRY OUT THE IC COOLANT TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- NOTE: Make sure to set the scan tool to 0 or full cold before beginning this step.
- Select the IC temperature gauge (ENGCOOLNT) active command and command the temperature gauge on then off. Observe the temperature gauge. The temperature gauge starts at cold (C) and moves to full hot (H).
- Is the temperature gauge within specifications?

Yes
GO to D2.

No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

-------------------------------------------------
D2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST


- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any PCM DTCs recorded?

Yes
REFER to Computers and Control Systems Information.

No
GO to D3.

-------------------------------------------------
D3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded IC DTCs from the self-test.
- Is DTC U0100 recorded?

Yes
GO to Pinpoint Test AU. Pinpoint Tests AU: DTC U0100

No
INSTALL a new PCM. REFER to Computers and Control Systems. TEST the system for normal operation.

-------------------------------------------------