Refer to
IAC Valve, PNP, and Ignition Switch
for wiring view.
Diagnosis
The following tables will diagnose the Temp Lamp circuits. Refer to Powertrain Control Module/EEPROM Replacement/Programming for PCM replacement.
Circuit Description
The Temp lamp is connected to battery voltage through the ignition switch. The PCM energizes the bulb by supplying a ground path through the Output Driver Module.
Diagnostic Aids
Refer to Temperature vs Resistance table to check for a skewed ECT sensor. A skewed ECT sensor may cause the temp lamp to illuminate without an actual overheating condition.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
The Powertrain OBD System Check prompts the technician to store the Freeze Frame Data in the scan tool. This will create an electronic copy of the freeze frame data taken when the fault occurred that can be referred to later.
-
Check for a faulty Temp Lamp bulb when checking for an open circuit.
-
Replacement PCM's must be programmed. Refer to the latest Techline information for programming procedures
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | |||
Turn the ignition switch ON, with the engine OFF. Is the temp lamp indicator ON? | -- | |||
3 |
Is the temp lamp indicator ON? | -- | Go to Diagnostic Aids | |
4 |
Is the engine coolant temperature greater than the specified value? | 123°C (253°F) | ||
5 | Using the scan tool command the cooling fan ON and OFF. Does the cooling fan go ON and OFF when commanded? | -- | Go to Section 6B Cooling and Radiator | |
6 |
Is the test light ON? | -- | ||
7 | Check for an short to ground on the Temp Lamp circuit, Repair as necessary. Was a repair necessary? | -- | ||
8 | With the ignition switch OFF. Disconnect PCM connector C3 (blue). Turn the ignition switch ON, connect a test light to ground and to the Temp lamp circuit terminal. Does the Temp lamp or test light illuminate? | -- | ||
9 | Check for an short to B+ on the Temp Lamp circuit . Was a problem found? | -- | ||
10 | Check the PCM connections, make sure they are clean and tight. Repair as necessary. Are any repairs necessary? | -- | ||
Replace the PCM? Is the action complete? | -- | -- | ||
12 | Check for an open fuse #9 and connecting circuits and repair as necessary, Refer to Section 8A . Was a repair necessary? | -- | ||
13 | Check for an open in the Temp Lamp circuit. Repair as necessary. Was a problem found? | -- | ||
14 | Check the Instrument Panel for a fault, Refer to Section 8C and repair as necessary Is the action complete? | -- | -- | |
15 | Using the scan tool command the Temp Lamp ON and OFF. Does the Temp Lamp go ON and OFF when commanded? | -- | System OK |
