Pinpoint Test E: Incorrect Temperature Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test E: Incorrect Temperature Gauge Indication
Normal Operation
The PCM receives the Engine Coolant Temperature (ECT) status through hardwired circuitry to the Cylinder Head Temperature (CHT) sensor. The Instrument Cluster (IC) receives the ECT data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IC monitors the ECT 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 ECT 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 ECT 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 E: INCORRECT TEMPERATURE GAUGE INDICATION
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E1 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 E2.
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E2 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 AT. Pinpoint Tests AT: DTC U0100
No
GO to E3.
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E3 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.
- Select the IC temperature gauge active command (ENGCOOLNT) and command the temperature gauge to approximately 89°C (192°F), 133°C (271°F), 155°C (311°F), then 0°C (32°F). Observe the temperature gauge. The temperature gauge starts at cold (C) and moves to full hot (H).
- Does the temperature gauge begin at cold (C) and move to mid-range at 89°C (192°F), hot (H) at 133°C (271°F), full hot (H) at 155°C (311°F), then return to 0°C (32°F)?
Yes
GO to E4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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E4 CHECK THE PCM TEMPERATURE PIDs
NOTE: The coolant temperature should range between 42-49°C (108-120°F) with the gauge in the cold (C) range, between 58-117°C (136-243°F) with the gauge in the normal range and between 119-121°C (247-250°F) with the gauge in the hot (H) range.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Start the engine.
- Select the PCM cylinder head temperature sensor PID (CHT_F) and monitor the PID while the engine is running.
- Does the PCM PID agree with the position of the temperature gauge indication?
Yes
INSTALL a new CHT sensor. TEST the system for normal operation.
If the concern is still present, INSTALL a new PCM. TEST the system for normal operation.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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