Circuit Description
The fuel pump relay is located in the underhood fuse block (UHFB). The engine control module (ECM) controls the fuel pump motor by supplying a ground to the fuel pump relay coil whenever the engine is cranking or running. When the fuel pump relay is commanded OFF, circuit not grounded, the voltage level at the ECM should be high, ignition voltage. When the fuel pump relay is commanded ON, circuit grounded, the voltage level at the ECM should be low. The ECM fuel pump relay feedback circuit uses a pull-up voltage, 2.6-4.6 volts, which allows the ECM to individually differentiate between an open, short to ground, or short to voltage. DTC P0232 will set if the ECM detects higher than normal feedback voltage when the fuel pump relay is commanded ON with the engine cranking/running.
Conditions for Setting the DTC
DTC P0232 will set if fuel pump relay feedback voltage is greater than 4.6 volts when the fuel pump relay is commanded ON when:
| • | The condition exists for longer than 0.5 seconds. |
| • | The engine speed is greater than 40 RPM. |
| • | The battery voltage is between 7.5-15 volts. |
DTC P0232 diagnostic runs continuously once the above conditions have been met.
DTC P0232 is a type D DTC.
Diagnostic Aids
Important: The ECM will only energize the fuel pump relay when the engine is cranking or running. If the ignition is turned ON and the engine is not cranking, the fuel pump will NOT run.
To locate an intermittent problem, use the scan tool to command the FUEL PUMP RELAY ON and OFF while wiggling circuit 497.
Fuel pump relay coil resistance is 70-115 ohms.
