Temperature Gauge: Testing and Inspection

Coolant Temperature Gauge Troubleshooting

Before testing, check the No.9 (7.5 A) fuse in the underdash 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 Malfunction Indicator Lamp (MIL).

Does the MIL came on?

YES - Troubleshoot the cause of the ECM/PCM DTC, and recheck.

NO - Go to step 2.

2. Check for a multiplex control unit DTC.

Is a DTC indicated?

YES - Troubleshooting the cause of the multiplex control unit DTC, and recheck.

NO - Go to step 3.

3. Do the communication line check with the self- diagnosis procedure.

Is the word "Error", indicated on the odo/trip display?

YES - The gauge cannot receive the signal from the multiplex control unit and the ECM/PCM. Check for an open in the WHT/GRN wire (gauge connector terminal B13).

NO - Go to step 4.

4. Do the gauge drive circuit check with the self- diagnosis procedure.

Dose 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 assembly.

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

Did the symptom/indication go away?

YES - Replace the ECM/PCM.

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