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DTC P0231, P0232, or P023F

DTC P0231, P0232, or P023F

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 Voltage

DTC P0232

Fuel Pump Control Circuit High Voltage

DTC P023F

Fuel Pump Control Circuit

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Control P0231 P023F P0232 P023F, P2635
Low Reference - P023F - P023F, P2635


Circuit/System Description

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module is active for 2 seconds if the engine is not in one of the modes for Crank (starting) or Run (driving). When this activity voltage is received, the fuel pump's control module supplies a varying voltage to the fuel pump module in the tank in order to maintain the desired fuel line pressure.

Conditions for Running the DTC

P0231, P023F

The ignition voltage is between 9-18 V.

P0232

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

Conditions for Setting the DTC

The fuel pump control module detects a fault on the fuel pump voltage circuit that is less than 11 V or greater than 18 V.

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC

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

Diagnostic support

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.

On vehicles with direct injection engines and mechanical high-pressure pump the vehicle can be driven for a time even if the pump in the fuel tank is not working.

Reference Information

Schematic Reference

Engine Controls Schematics (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel System Description (LF1) Fuel System Description (LAU or LY7)

Electrical Information Reference


Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the A7 fuel pump and level sensor assembly.

2. Connect a test lamp between the control circuit terminal A and ground.

3. Ignition ON, command the ECM fuel pump enable command ON and OFF with a scan tool. The test lamp should turn ON and OFF, when changing between the commanded states.

4. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module.

5. 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 K27 fuel pump control module.

6. Ignition OFF, connect a test lamp between the control circuit terminal A and the low reference circuit terminal B.

7. Ignition ON, command the ECM fuel pump enable command ON with a scan tool. The test lamp should illuminate.

8. If the test lamp does not illuminate, test the low reference circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.

9. If all circuits test normal, replace the A7 fuel pump and level sensor assembly.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.


Primary Fuel Tank Module Replacement (NA3, NE9, NF9) ; Primary Fuel Tank Module Replacement (NT7, NU5)

Control Module References for fuel pump control module replacement, programming and setup