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

The Main Relay (also referred to as Fuel Injection or EGI Relay), located on the left side of the engine compartment in a relay panel, supplies power to the ECU and a number of ECU controlled devices when the ignition is switched "ON", including the crank angle sensor, fuel injectors, and a variety of solenoid valves.

The ECU energizes these devices when needed by completing the circuit to ground.