Pinpoint Tests AB: The Engine Over-Temperature Message Center Warning Indicator Is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Test AB: The Engine Over-Temperature Message Center Warning Indicator Is Never/Always On

Normal Operation

The Instrument Panel Cluster (IPC) receives the engine over-temperature command from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. If the PCM detects an engine over-temperature condition or has entered into the fail-safe cooling mode, the PCM sends a command to the IPC to turn the engine over-temperature warning message indicator on. The PCM provides a fail-safe cooling strategy that begins limiting engine performance and provides engine shut down in the event that the engine has reached an over-temperature condition.

If the engine over-temperature message is missing or invalid for less than 5 seconds, the engine over-temperature message center warning indicator remains in the last state (on or off) based upon the last known good message received.

If the engine over-temperature message is missing for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the engine over-temperature warning message center indicator on.

NOTE: If DTC U0100:00 is set in the IPC, other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM concern
- IPC

PINPOINT TEST AB: THE ENGINE OVER-TEMPERATURE MESSAGE CENTER WARNING INDICATOR IS NEVER/ALWAYS ON

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AB1 CHECK THE MESSAGE CENTER WARNING INDICATOR FUNCTION

- Close all doors, hood and liftgate.
- Ignition ON.
- Open the driver door while monitoring the door ajar message center warning indicator.
- Does the driver door ajar message center warning indicator turn off with the driver door closed and turn on with the driver door open?

Yes
GO to AB2.

No
GO to Pinpoint Test AD. Pinpoint Tests AD: The Message Center Is Not Operating Correctly

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AB2 RETRIEVE THE RECORDED DTCs FROM 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 the Computers and Control Systems.

No
GO to AB3.

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AB3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST

- Check for recorded DTCs from the IPC self-test.
- Is DTC U0100:00 recorded?

Yes
GO to Pinpoint Test AO. Pinpoint Tests AO: DTC U0100:00

No
If the engine over-temperature message center warning indicator is never on, the system is functioning normally.

If the engine over-temperature message center warning indicator is always on, INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.

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