Fuel Pump Electrical Circuit Diagnosis

FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS

CIRCUIT DESCRIPTION
The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within two seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within two seconds if ignition reference pulses cease to be detected and the ignition remains ON.

TEST DESCRIPTION

Steps 1 - 12:

Steps 13 - 24:

Steps 25 - 27:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the condition is located on the coil side or on the switch side of the fuel pump relay.
3. This step verifies that the engine control module (ECM) is providing voltage to the fuel pump relay.
4. This step tests for an open in the ground circuit to the fuel pump relay.
5. This step determines if a voltage is constantly being applied to the fuel pump relay.
12. This step determines if the condition with the circuit is intermittent.