Component Tests and General Diagnostics

Coolant Temperature Gauge Troubleshooting

Before testing, check the No. 9 (10 A) fuse in the under-hood fuse/relay box and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box.

1. Start the engine, and check the ECM/PCM for DTCs with the HDS.

Are there stored DTCs in the ECM/PCM?
YES - Troubleshoot the cause of the ECM/PCM DTC, Initial Inspection and Diagnostic Overview and recheck.

NO - Go to step 2.


2. Check for DTCs in the body electrical system with the HDS.

Is a DTC indicated?
YES - Troubleshoot the cause of the body electrical system DTC, Multiplex Control System Troubleshooting and recheck.

NO - Go to step 3.


3. Do the communication line check with the self-diagnostic procedure. Initial Inspection and Diagnostic Overview

Is the word "Error" indicated on the odo/trip display?
YES - The gauge control module cannot receive the signal from the multiplex control unit and the ECM/PCM. Check for an open in the WHT and RED wire (gauge control module connector terminals No. 28 and No. 29).

NO - Go to step 4.


4. Do the gauge control module drive circuit check with the self-diagnostic procedure. Initial Inspection and Diagnostic Overview

Does the temperature gauge needle sweep from the minimum position to the maximum, then return to the minimum position?
YES - Go to step 5.

NO - Replace the gauge control module.


5. Substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview and recheck.

Does the symptom/indication go away?
YES - Replace the ECM/PCM.

NO - Substitute a known-good gauge control module. If the symptom/indication goes away, replace the gauge control module.