Pinpoint Test K: The Engine Over-Temperature Warning Indicator Is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test K: The Engine Over-Temperature Warning Indicator Is Never/Always On

Normal Operation

The engine over-temperature warning indicator informs the driver that the engine coolant is overheating due to loss of engine coolant fluid or other causes, and that the PCM is in failsafe cooling mode. The PCM provides the engine over-temperature information to the Instrument Cluster (IC) to illuminate the engine over-temperature warning indicator and send the temperature gauge to the full hot position.

If the engine temperature data is missing or invalid for 5 seconds or less, the IC defaults the temperature gauge to the last setting and the engine over-temperature warning indicator remains off, based upon the last known good temperature status message. If the IC does not receive the engine temperature data status message from the PCM for more than 5 seconds, the IC sets DTC U0101 in continuous memory and defaults the temperature gauge to cold (C) and the engine over-temperature warning indicator on. If the engine temperature data and failsafe status message is invalid for more than 5 seconds, the IC sets DTC U2023 in continuous memory and defaults the temperature gauge to cold (C).

NOTE: If DTC U0101 is set in the IC, other observable symptoms may be an inoperative tachometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following:

- PCM
- IC


PINPOINT TEST K: THE ENGINE OVER-TEMPERATURE WARNING INDICATOR IS NEVER/ALWAYS ON

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K1 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST


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

Yes
REFER to Computers and Control Systems Information.

No
GO to K2.

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K2 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC failsafe warning indicator (OVTEMP_LMP) active command on and off while monitoring the engine over-temperature warning indicator.
- Does the engine over-temperature warning indicator illuminate when commanded on and turn off when commanded off?

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) Instrument Cluster (IC). TEST the system for normal operation.

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