Fuel Pump Relay

Fuel Pump Relay

The fuel pump relay is located in the engine compartment fusebox which is positioned on the LH side of the engine compartment. The relay is normally open when the ignition is off.

When the ignition switch is in position II (ignition on), the ECM provides an earth path for the relay coil on pin 68 of connector C0913. With the ignition on, the relay receives a feed from the main relay which energises the relay coil, closing the contacts.

A permanent battery supply is provided to the relay contacts from fuse 10 in the engine compartment fusebox, via the fuel shut-off switch. The feed passes through the relay contacts and operates the fuel pump to pressurise the fuel system. The relay will be energised for a short time only to pressurise the fuel system.

When the ignition switch is moved to position III (crank), the ECM will energise the relay when the engine starts cranking and will remain energised until the engine stops.

If the engine stalls and the ECM stops receiving a signal from the CKP sensor, the ECM will remove the earth path for the relay, stopping the fuel pump.

The fuel shut-off switch, when tripped, cuts off the power supply to the relay contacts, disabling the fuel pump in the event of a sudden deceleration. If the fuel pump fails to operate, check that the fuel shut-off switch is not tripped. The switch is reset by depressing the rubber cap on the top of the switch.

WARNING: Ensure there are no fuel leaks and confirm the integrity of the fuel system before resetting the fuel shut-off switch.

If the fuel pump relay fails, power will not be supplied to the fuel pump and the engine will not start or will stop if already running due to fuel starvation. The ECM will store fault codes which can be retrieved using TestBook.