PCM Controlled Warning Lamps Diagnosis

DIAGNOSIS

The following tables will diagnose the Temp Lamp circuits. Refer to PCM/EEPROM Replacement/programming for PCM replacement.


CIRCUIT DESCRIPTION

The Temp lamp is connected to baftery 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 Engine Coolant Temperature (ECT) sensor. A skewed ECT sensor may cause the temp lamp to illuminate without an actual overheating condition. Specifications

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain On-Board Diagnostics (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.

2. Check for a faulty Temp Lamp bulb when checking for an open circuit.

11. Replacement PCM's must be programmed. Refer to the latest Techline information for programming procedures