Fuel Pump Relay: Description and Operation

Relay Center:

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