Temperature Warning Lamp/Indicator: Testing and Inspection

Chart C-16:

Wiring Diagram:

CIRCUIT DESCRIPTION:


The TEMP light is powered through the gauges fuse by ignition #3. The PCM illuminates the bulb by supplying a path to ground through quad-driver module #3(B) when the engine temperature is above 124°C (255°F).

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. With the ignition "ON" and engine "OFF," the PCM should be grounding circuit 1268.

2. The TEMP light should only be controlled to be turned "ON" while the engine is running when the coolant temperature is above 124°C (255°F).

DIAGNOSTIC AIDS

The coolant temperature sensor, in rare cases, may fail to indicate the correct engine coolant temperature without setting a malfunction code. This could result in turning "ON" the TEMP light without having a overheating condition. It could also result in overheating without the "Temp"/"Check Gauges" light being turned "ON." See "coolant sensor temperature vs. resistance values" diagnostic aids table on CHART 15 chart or compare coolant temperature reading on the scan tool with actual coolant temperature. Replace coolant temperature sensor is mis-scaled.