Main Relay (Computer/Fuel System): Description and Operation

OPERATION
- While the ignition switch is on, battery power is supplied to the engine control module, the injector, the volume air flow sensor, etc.
- When the ignition switch is turned on, the battery voltage is applied from the ignition switch to the engine control module, which then turns ON the power transistor to energize the MFI relay coil. This turns ON the MFI relay switch and the power is supplied from the battery to the engine control module through the MFI relay switch.