The engine control module (ECM) supplies voltage to the fuel pump flow control module (FPCM) when the ECM detects that the ignition is on. The voltage from the ECM to the FPCM remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the FPCM supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

P0231

The ignition voltage is between 9-18 volts

P0232

The control enable voltage signal supplied for the ECM to FPCM is inactive for 4 seconds after engine has been shut off.

P023F

The ignition voltage is between 9-18 volts

The FPCM detects a fault on the fuel pump voltage circuit that is above or below a predetermined voltage threshold.

DTCs P0231, P0232, and P023F are Type A DTCs.

DTCs P0231, P0232, and P023F are Type A DTCs.

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the fuel pump ON and OFF using the scan tool ECM fuel pump output control. The fuel pump should turn ON and OFF.

1. Ignition OFF, disconnect the harness connector at the fuel pump.
2. Connect a test lamp between the control circuit terminal D and ground.
3. Ignition ON, command the fuel pump ON and OFF using a scan tool ECM fuel pump output control. The test lamp should turn ON and OFF, as commanded.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the FPCM.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FPCM.

4. Ignition OFF, connect a test lamp between the control circuit terminal A and the control circuit terminal D.
5. Ignition ON, command the fuel pump ON using a scan tool. The test lamp should illuminate.

⇒	If the test lamp does not illuminate, test the control circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the FPCM.

6. If all circuits test normal, replace the fuel tank fuel pump module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.