Ignition Relay: Testing and Inspection

Ignition Relay Diagnosis

Circuit Description

The ignition relay supplies ignition voltage to the following components:

* Fuel injectors
* Ignition coils
* Powertrain control module (PCM)
* Alternator/generator

Diagnostic Aids

If the relay fails close:

* Scan data WILL be available.
* Vehicle WILL crank, no start.
* Instrument panel indicator lights WILL illuminate.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. This step is testing for battery positive voltage supply, hot at all times, to the IGN relay switching contacts.
3. This step is testing for battery positive voltage supply, hot in Run and Start, to the coil of the IGN relay.
4. This step is testing the IGN relay coil ground circuit.
5. This step is testing the IGN relay load circuit feed to circuit breakers and fuses.