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

Relays And Electronic Control Units:

PURPOSE
The main relay supplies power to the supplementary air valve, airflow meter, fuel injectors and fuel pump relay.

The relay also applies power to the ECU, generating a system reset which causes the microprocessor to perform an initialization routine, condition input circuits for sensor scanning and run the fuel pump to pressurize the system for starting. The fuel pump relay is ECU timed to limit fuel pump operation to approximately 0.5 second prior to cranking.

OPERATION
The relay is energized when the ignition "ON" relay is energized by turning the ignition switch to position "II."

LOCATION
Beneath right side dash.