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

Main Relay:

PURPOSE
Supplies power to the Engine Control Module (ECM), injectors and the fuel pump.

OPERATION
The main relay, actually contains two individual relays.
One relay is energized whenever the ignition is on, and it supplies the battery voltage to the ECM, power to the injectors, and power to the second relay.
The second relay is energized for 2 seconds when the ignition is switched on before starting, and when the engine is running, to supply power to the fuel pump.