Main Relay

FAULT DIAGNOSIS, MAIN RELAY

Fault Symptom.
Engine fails to start.

Diagnostic Procedure.
1. Check whether the main relay is activated.
Ignition switch in the ON position.
Unplug the camshaft position sensors+ 3-pin connector.
Connect the test lamp to pin 1 of the female connector and a good ground on the engine.
- The test lamp should light up.
Turn the ignition switch to the OFF position.
- The test lamp should go out after five seconds.

If the test lamp lights up the main relay is OK.
If it does not, continue with step 2.





2. The relay does not operate or there is an open circuit in the wiring.
Check the main relay's electrical interface.
Remove the relay board and take our the main relay.
Ignition switch in the ON position.
Carry out the following tests:
^ Connect the test lamp across:
- pin 30 of the relay base and a good ground.
- pin 86 of the relay base and a good ground.
The test lamp should light up.

If it does not, it is not receiving current. Continue fault diagnosis in the Electrical System.





^ Connect a jumper lead across pins 30 and 87 of the relay base.
Connect the test lamp to pin 1 of the camshaft position sensor's female connector and a good ground on the engine.
The test lamp should light up.

If it does not, check the lead between pin 87 of the relay and pin 2 of the Idle Air Control valve connector for continuity.

^ Measuring the resistance of the relay coil.
Measure the resistance across pins 85 and 86 of the relay.
The resistance should be about 85 ohms.

If it is not, fit a new relay.
If all measurements are OK, check the lead between pin 85 of the relay and pin 46 of the control module for continuity.
If the lead is OK, continue at "Procedure Before ECM Replacement". Component Tests