Main Relay Test

Fault Symptom.
Engine Will Not Start





Diagnostic Procedure.
1 Check the fuses

- Check MAXI fuse 2 is the fuse intact?

YES
^ Continue with point 2.
NO
^ Change the fuse.

2 Check the operation of the main relay

- Turn the ignition switch to the ON position.
- Unplug the Idle Air Control (IAC) valve's 3-pin connector.
- Connect the test lamp to:
^ pin 2 and battery negative (B-).
The test lamp should light up.

Did the test lamp light up?

YES
^ The main relay is OK.
NO
^ Continue with point 2.





3 Check the power supply for the main relay circuit

- Turn the ignition switch to the ON position.
- Unplug the main relay from its socket.
- Connect the test lamp to:
^ pin 30 of the relay socket and a good grounding point.
^ pin 86 of the relay socket and a good grounding point.

Did the test lamp light up?

YES
^ Continue with point 4.
NO
^ Continue fault diagnosis in the electrical system, wiring diagrams.





4 Check the relay output

- Remove the IAC valve.
- Connect a test lamp to:
^ pin 2 and battery negative (B-).
- Connect a jumper lead to the relay socket between:
^ pins 30 and 87.
The test lamp should light up.

Did the test lamp light up?

YES
^ Continue with point 5.
NO
^ Check the lead for continuity/shorting to ground and repair or replace it if necessary.

5 Check the control module's output

- Connect a test lamp to the relay socket between:
^ Pins 30 and 85.
- Turn the ignition switch to the ON position.
The test lamp should light up.

Did the test lamp light up?

YES
^ Change the main relay.
NO
^ Check the lead between pin 85 of the relay and pin 27 of the control module for continuity.

If the lead is OK, continue at "Before Replacing a Control Module". Component Tests and General Diagnostics