jaguar Workshop Repair Guides

Jaguar Workshop Service and Repair Manuals

Relays and Modules - Emission Control Systems > < Diagram Information and Instructions|Page 1772
Page 1
background image

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

PURPOSE

The main relay supplies power to the supplementary air valve, air mass 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."

Relays And Electronic Control Units

LOCATION

Beneath right side dash.

Relays and Modules - Emission Control Systems > < Diagram Information and Instructions|Page 1772