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

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 cause, and that the PCM is in failsafe cooling mode. The PCM incorporates 2 strategies for failsafe 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. In both strategies, 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 and failsafe data is missing or invalid for 5 seconds or less, the instrument cluster (IC) defaults the temperature gauge to the last setting and the engine overtemperature warning indicator remains off, based upon the last known good temperature status message. If the instrument cluster (IC) does not receive the engine coolant temperature and failsafe status message from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0101 in continuous memory and defaults the temperature gauge to cold (C) and the engine overtemperature warning indicator on. If the engine coolant temperature and failsafe status message is invalid for more than 5 seconds, the instrument cluster (IC) sets DTC U2023 in continuous memory and defaults the temperature gauge to cold (C).

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

This pinpoint test is intended to diagnose the following:
- PCM
- Instrument cluster (IC)

K1-K2:

K3-K4: