| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
Fuel pump has 2 speeds and is controlled by load on engine. When engine starts, fuel pump relay closes and battery voltage is applied directly to fuel pump (high speed). After engine starts, during idle or light loads, power is supplied to fuel pump via fuel pump resistor (low speed). DTC is set if there is an open or short in fuel pump relay circuit. Possible causes are
- Open or short in fuel pump relay circuit.
- Fuel pump relay.
- ECM.