Relays

The engine management system uses four relays:
- Starter motor, ECM (Z132) power supply (main relay), ignition and fuel pump, all located within the fusebox.

Main Relay
This relay supplies the power feed to the ECM (Z132) with a tap off to feed the fuel injectors and air flow meter. This relay is controlled by the ECM (Z132) itself, so that the ECM (Z132) remains powered up after the ignition is removed and the ECM (Z132) can record all temperature readings and motorize the Idle Air Control Valve (M112) to the fully open position. This is known as the "ECM (Z132) power down routine". Failure of this relay will cause the ECM (Z132) to not be switched on, resulting in absence of fuel and spark and therefore a failed start.

Ignition Relay
This relay is ignition key controlled and supplies a feed to the coils, evaporative emission canister purge valve and heated oxygen sensor. When the ignition key is turned oft, supply to the coils is cut immediately.

Starter Motor Relay
This relay is also ignition key controlled and is activated with the key in the ignition Ill position only. Releasing the key after cranking cuts supply to the relay and switches off the starter motor.

Fuel Pump Relay
This relay is fed from the ignition relay and controlled by the ECM (Z132). It is pulled in on ignition II position to prime the fuel system. If the key remains in the ignition II position, then the relay falls out after a few seconds, precisely when determined by the ECM (Z132).