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

MFI Main Relay:

PURPOSE
The MFI main relay controls the ECM power supply.

LOCATION
Located in the relay box on the left side of the engine compartment.

OPERATION
When the ignition switch is turned to the ON position, the ECM powers the relay coil through terminal M-REL. When powered the relay contacts close, sending battery voltage to ECM terminals +B and +B1.