Main Relay (Computer/Fuel System): Description and Operation
PURPOSE
The "EFI Main" relay serves as a source of battery power for several components including the circuit opening relay, (which powers the fuel pump), and the Engine Control Module (ECM).
OPERATION
ECM Main Power Circuit:
The main relay is energized by a signal from the ignition switch. It then supplies battery current from the "EFI" fuse to the ECM and other components.