Component Tests and General Diagnostics

Coolant Temperature Gauge Troubleshooting

NOTE: 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, 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.

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 Service and Repair.�

5. Substitute a known-good ECM/PCM, and recheck.

Does the symptom/indication go away?

YES -

Replace the ECM/PCM ECM/PCM Replacement (A/T).�

NO -

Substitute a known-good gauge control module. If the symptom/indication goes away, replace the original gauge control module Service and Repair.�