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." These devices include the crank angle sensor, fuel injectors and a variety of solenoid valves. The ECU completes the circuit by grounding these devices when indicated by its calculations.