Main Relay (Computer/Fuel System): Testing and Inspection

Main Relay Circuit Check

Wiring Diagram:

Circuit Description

When the ignition is turned ON or to the START position, the main relay is energized. The main relay then supplies voltage to the engine fuse box fuse Ef24 and the engine fuse box fuse Ef27.

Step 1 - 5:

Step 6 - 14:

Diagnostic Aids

- An intermittent problem may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.
- A faulty main relay will cause a no start condition. There will be no voltage supplied to the fuel injectors. Without voltage supplied to the fuel injectors, they will not operate.