Pinpoint Test C: The Temperature Gauge Is Inoperative

Instrumentation and Warning Chimes

Pinpoint Tests

Pinpoint Test C: The Temperature Gauge Is Inoperative

Normal Operation

The PCM uses the Cylinder Head Temperature (CHT) sensor to measure the engine temperature. 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 engine temperature data is missing or invalid 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, the IC sets DTC U0100 in continuous memory and defaults the temperature gauge to cold (C). If the engine temperature status message is invalid for more than 5 seconds, the IC sets DTC U2199 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 tachometer, speedometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM
- IC


PINPOINT TEST C: THE TEMPERATURE GAUGE IS INOPERATIVE

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C1 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST


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

Yes
REFER to Computers and Control Systems.

No
GO to C2.

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C2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


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

Yes
For DTC U0100, GO to Pinpoint Test AJ. Pinpoint Test AJ: DTC U0100

For all other DTCs, REFER to DTC Charts. Diagnostic Trouble Code Tests and Associated Procedures

No
GO to C3.

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C3 CARRY OUT THE TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.

- NOTE: The coolant temperature should range between [-]40-59°C (40-138°F) with the gauge in the cold (C) range, between 60-120°C (140-248°F) with the gauge in the normal or mid-range and above 121-123°C (250-253°F) with the gauge in the hot (H) range.

- Select the IC temperature gauge (ENGCOOLNT) active command. Command the temperature gauge to the approximate values in the following table while monitoring the gauge.





- Does the temperature gauge operate according to the above specifications?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.

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

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