Fuel Pump Electrical Circuit Diagnosis
CIRCUIT DESCRIPTIONWhen you turn ON the ignition switch, the control module enables the fuel pump relay which powers the fuel pump ON. The fuel pump remains ON as long as the engine is cranking or running and the control module receives ignition reference pulses. If there are no ignition reference pulses, the control module shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops.
TEST DESCRIPTION
Steps 1-9:
Steps 10-21:
Steps 22-25:
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the condition is current.
4. This step verifies that the PCM is providing voltage to the fuel pump relay.
5. This step tests for an open in the ground circuit to the fuel pump relay.
6. This step determines if a voltage is constantly being applied to the fuel pump relay.
13. This step determines if the condition with the circuit is intermittent.
15. This step determines if the fuel pump will operate while by-passing the fuel pump relay.