Main Relay (Computer/Fuel System): Description and Operation
DESCRIPTION AND OPERATIONWhile the ignition switch is ON, battery power is supplied to the engine control module, the injector, etc.
When the ignition switch is turned ON, current flows from the ignition switch through the MFI relay coil to ground. This turns ON the MFI relay switch and power is supplied from the battery through the MFI relay switch to the engine control module.