Oil Pressure Sensor: Description and Operation

Wiring Diagram For Fuel Pump Circuit:

When the ignition key is first turned to the "ON" position, the ECM will energize the fuel pump for two seconds. This increases fuel pressure for cranking. If the engine is not running within two seconds, the ECM will shut off the pump and wait until the engine starts.

The Oil pressure switch is wired in parallel to the circuit to operate the fuel pump circuit in case of failure of the fuel pump relay. Failure of the fuel pump relay cold cause increased cranking time during cold start up.