Fuel Pump Signal: Description and Operation

FUEL PUMP ELECTRICAL CIRCUIT
When the key is first turned ON the PCM energizes the fuel pump relay for two seconds to build up the fuel pressure quickly. If the engine is not started within two seconds, the PCM shuts the fuel pump OFF and waits until the engine is cranked. When the engine is cranked and the RPM signal has been detected by the PCM, the PCM supplies 12 volts to the fuel pump relay to energize the electric in-tank fuel pump.
An inoperative fuel pump relay can result in a no start condition.
An inoperative fuel pump would cause a no start condition. A fuel pump which does not provide enough pressure can result in poor performance.

FUEL LEVEL SENSOR PCM INPUT
The fuel level sensor input to the PCM is used to determine if the fuel level in the tank is correct to run the EVAP diagnostic tests. To ensure sufficient volume in the tank to begin the various diagnostic tests, the fuel level must be between 15% and 85%.