Ignition Relay Diagnosis

Circuit Description

The IGN relay powers the following components:

^ Injectors/Ignition coils
^ Transmission
^ A/C system
^ [1][2]EVAP solenoid and EVAP Vent Valve
^ MAF sensor
^ Heated Oxygen Sensors

Diagnostic Aids

^ The following may cause an intermittent:
- Poor connections, Refer to Intermittents and Poor Connections Diagnosis. Intermittent Conditions
- Corrosion
- Mis-routed harness.
- Rubbed through wire insulation.
- Broken wire inside the insulation
^ For an intermittent, refer to Symptoms. Symptom Related Diagnostic Procedures

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A. Using this kit prevents damage to the harness connector terminals.
5. This step isolates the circuit from the IGN relay. All of the circuits at the relay are good if the test lamp illuminates.
8. Inspect the fuses for the IGN relay for being open. If a fuse is open inspect the circuits for a short to ground.
9. Inspect the fuses for the IGN relay for being open. If a fuse is open, inspect the circuits for a short to ground.
11. Remove the underhood electrical center and inspect the circuits that are supplied a voltage by the IGN relay.