Engine Coolant Temperature Indicator Always On

Engine Coolant Temperature Indicator Always On

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The instrument panel cluster (IPC) illuminates the TEMP indicator when the engine control module (ECM) determines that the coolant temperature is more than 128°C (262°F). The IPC receives a discrete input from the ECM requesting illumination.

The IPC illuminates the TEMP indicator during the display test at the start of each ignition cycle.

Reference Information

Schematic Reference

* Instrument Cluster Schematics
* Engine Cooling Schematics

Connector End View Reference

* Displays and Gages Connector End Views
* Cooling System Connector End Views

Description and Operation

* Instrument Cluster Description and Operation
* Cooling System Description and Operation
* Engine Overheating

Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids
* Wiring Repairs

Scan Tool Reference

* Scan Tool Output Controls
* Scan Tool Data List
* Scan Tool Data Definitions

Circuit/System Testing

With the engine running within the normal operating temperature range, the engine coolant temperature (ECT) indicator should not be illuminated.

If the engine coolant is not within the normal operating range, repair the overheating condition.
If the engine coolant is within the normal operating range, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Programming and Relearning, Testing and Inspection