Pinpoint Test D: Incorrect Temperature Gauge Indication

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test D: Incorrect Temperature Gauge Indication

Normal Operation

The PCM receives the Engine Coolant Temperature (ECT) status through hardwired circuitry to the ECT sensor (2.3L and 3.0L engines) or to the Cylinder Head Temperature (CHT) (3.5L engine). The Instrument Cluster (IC) receives the ECT data from the PCM over the communication network. The IC monitors the ECT data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

This pinpoint test is intended to diagnose the following:

- ECT sensor
- CHT sensor
- PCM
- IC



PINPOINT TEST D: INCORRECT TEMPERATURE GAUGE INDICATION

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D1 CHECK FOR CORRECT OPERATION OF THE COOLING SYSTEM


- Verify that the engine cooling system and thermostat are functioning correctly.
- Are the engine cooling system and thermostat operating correctly?

Yes
GO to D2.

No
REFER to Cooling System.

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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 DTCs recorded?

Yes
REFER to Computers and Control Systems Information to continue diagnosis of the DTCs.

No
GO to D3.

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D3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded continuous memory IC DTCs.
- Is DTC U1900 recorded?

Yes
REFER to Information Bus to diagnose communication with the PCM.

No
GO to D4.

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D4 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: The coolant temperature should range between 0-59°C (32-138°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 123°C (253°F) with the gauge in the hot (H) range.
- Select the IC temperature gauge (ENGCOOLNT) active command. Command the temperature gauge according to the following table:





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

Yes
GO to D5.

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

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D5 CHECK THE PCM TEMPERATURE PIDs


- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Start the engine.
- Select the PCM ECT (2.3L and 3.0L engines) or Cylinder Head Temperature (CHT) (3.5L engine) PID and monitor the PID while the engine is running.
- Does the PID agree with the position of the temperature gauge?

Yes
INSTALL a new ECT (2.3L and 3.0L) or CHT (3.5L) sensor. REFER to Section Computers and Control Systems Information.
TEST the system for normal operation.

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

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