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

If the engine temperature data is missing for 5 seconds or less or if the IPC receives invalid engine temperature data for 5 seconds or less, the IPC defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the IPC does not receive the engine temperature status message from the PCM for more than 5 seconds, the IPC sets DTC U0100:87 in continuous memory and defaults the temperature gauge to cold (C). If the engine temperature data is deemed invalid by the IPC for 5 seconds or more, the IPC sets DTC U0401:68 and defaults the temperature gauge to cold (C).

NOTE: If DTC U0100:87 is set in the IPC, other observable symptoms can be an inoperative tachometer, speedometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM
- IPC



PINPOINT TEST D: TEMPERATURE GAUGE INOPERATIVE

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D1 RETRIEVE THE RECORDED PCM DTCs FROM THE KOEO SELF-TEST


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

Yes
REFER to Computers and Control Systems Information.

No
GO to D2.

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D2 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST


- Check for recorded DTCs from the IPC self-test.
- Are any DTCs retrieved?

Yes
For DTC U0100:87, GO to Pinpoint Test AQ. Pinpoint Tests AQ: DTC U0100:87

For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes

No
GO to D3.

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D3 CARRY OUT THE IPC COOLANT TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger.
- Select the IPC temperature gauge (ENGCOOLNT) active command on and off while monitoring the temperature gauge.
- Does the temperature gauge start at C (cold) when at 0%, and move to H (hot) at 100%?

Yes
INSTALL a new PCM. REFER to Computers and Control Systems. TEST the system for normal operation.

No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Service and Repair. TEST the system for normal operation.

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