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

Instrumentation, Message Center and Warning Chimes

Pinpoint Test N: The Engine Over-Temperature 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 (Instrument Panel Cluster) to turn the engine over-temperature warning indicator on. The PCM incorporates 2 strategies for fail-safe cooling in the event that the engine has reached an over-temperature condition. The first strategy is when the PCM provides engine operation but takes on the limp home strategy. The second strategy is when the PCM determines that the engine is sufficiently over-temperature and is about to be shut down by the PCM.

If the engine over-temperature status message is missing or invalid for less than 5 seconds, the engine over-temperature warning indicator remains in the last on/off state, based upon the last known good engine over-temperature status message received. If the engine over-temperature message is invalid for more than 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0401:68 in continuous memory and defaults the engine message center indicator on.

If the engine over-temperature status message is missing for more than 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0100:87 in continuous memory and defaults the engine over-temperature warning indicator on.

NOTE: If DTC U0100:87 is set in the IPC (Instrument Panel Cluster) , other observable symptoms can be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM

- IPC (Instrument Panel Cluster)

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

N1 CARRY OUT THE IPC (Instrument Panel Cluster) WARNING LAMPS AND CHIME ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) DataLogger.

- Select the engine over-temperature warning indicator (COOLANT_LMP) active command. Command the engine over-temperature warning indicator on and off while observing the engine over-temperature warning indicator.

Does the over-temperature warning indicator illuminate when commanded on, and turn off when commanded off?

Yes
GO to N2.

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

N2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) 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 N3.

N3 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST

- Check for recorded DTCs from the IPC (Instrument Panel Cluster) self-test.

Are any DTCs recorded?

Yes
For DTC U0100:87, GO to Pinpoint Test AQ Pinpoint Test AQ: DTC U0100:87.

For DTC U0401:68, RETRIEVE and REPAIR all non-network DTCs in the PCM and other modules on the network.

For all other DTCs, REFER to DTC Charts Instrumentation, Message Center and Warning Chimes.

No
INSTALL a new PCM. TEST the system for normal operation.