Pinpoint Test X: The Engine Coolant Over-Temperature Warning Indicator Is Never/Always On (Base IC)

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test X: The Engine Coolant Over-Temperature Warning Indicator Is Never/Always On (Base IC)

Normal Operation

The PCM receives the Engine Coolant Temperature (ECT) status through hardwired circuitry to the ECT sensor (4.0L engine), or from the Cylinder Head Temperature (CHT) sensor (4.6L engine). The Instrument Cluster (IC) receives the ECT data from the PCM over the High Speed Controller Area Network (HS-CAN). The IC monitors the engine temperature data received from the PCM and when the engine temperature is high, the engine over-temperature warning indicator illuminates.

This pinpoint test is intended to diagnose the following:

- PCM
- IC



PINPOINT TEST X: THE ENGINE COOLANT OVER-TEMPERATURE WARNING INDICATOR IS NEVER/ALWAYS ON (BASE IC)

-------------------------------------------------
X1 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 PCM DTCs recorded?

Yes
REFER to Computers and Control Systems Information.

No
GO to X2.

-------------------------------------------------
X2 CARRY OUT THE IC INDICATOR LAMP ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC all lamps active command (ALL_LAMP). Command all the lamps on and off. Observe the engine coolant over-temperature warning indicator.
- Does the engine coolant over-temperature warning indicator illuminate when commanded on, and turn off when commanded off?

Yes
INSTALL a new PCM. REFER to Computers and Control Systems. 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.

-------------------------------------------------