Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0231: Fuel Pump Control Circuit Low VoltageDTC P0232: Fuel Pump Control Circuit High Voltage
DTC P023F: Fuel Pump Control Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Fuel Pump High Control | P0231 | P023F | P0232 | P023F, P2635 |
Fuel Pump Low Control | -- | P023F | -- | P023F, P2635 |
Circuit/System Description
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 closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The FPCM detects a fault on the fuel pump voltage circuit that is above or below a predetermined voltage threshold. |
| • | The above condition is present for greater than 12.5 milliseconds. |
Action Taken When the DTC Sets
| • | DTCs P0231 and P023F are Type A DTCs. |
| • | DTC P0232 is a Type B DTC. |
Conditions for Clearing the DTC
| • | DTCs P0231 and P023F are Type A DTCs. |
| • | DTC P0232 is a Type B DTC. |
Diagnostic Aids
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.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the fuel pump ON and OFF using the scan tool FPCM output control. The fuel pump should turn ON and OFF.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel pump.
- Connect a test lamp between the control circuit terminal D and ground.
- Ignition ON, command the fuel pump ON and OFF using a scan tool. The test lamp should turn ON and OFF, as commanded.
- Ignition OFF, connect a test lamp between the control circuit terminal A and the control circuit terminal D.
- Ignition ON, command the fuel pump ON using a scan tool. The test lamp should illuminate.
- If all circuits test normal, replace the fuel tank fuel pump module.
| ⇒ | 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. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for FPCM replacement, setup, and programming |
