Fuel Pump Relay: Description and Operation

Circuit Opening Relay Circuit Schematic:

The Circuit Opening Relay, located near the ECU, is responsible for providing power to the Fuel Pump. Power is applied to the STA terminal of the relay from the starter when the ignition switch signals cranking mode. This allows the fuel pump to operate until the engine starts and runs under its own power. A signal from the Air Flow Meter (FC), keeps the relay closed until the ignition switch is turned OFF and de-energizes the EFI Main Relay. The fuel pump operation is then interrupted.