P023F
DTC P0231, P0232, or P023F
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions 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/System Description
The engine control module (ECM) supplies voltage to the fuel pump power control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump power control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump power control module supplies a varying voltage to the fuel tank fuel pump module in order to maintain the desired fuel line pressure.
Conditions for Running the DTC
P0231
* The ignition voltage is greater than 7 V.
* The engine is cranking or running.
* The fuel pump enable circuit is commanded ON.
* The DTC runs continuously when the conditions above are met.
P0232
* The ignition voltage is greater than 7 V.
* The fuel pump enable circuit is commanded ON.
* The DTC runs continuously when the conditions above are met.
P023F
* The ignition voltage is greater than 11 V.
* The commanded duty cycle is greater than approximately 50 percent.
* The DTC runs continuously when the conditions above are met.
Conditions for Setting the DTC
P0231
The fuel pump power control module detects that the fuel pump current is greater than 14.48 A for 1 s.
P0232
The fuel pump power control module detects that the fuel pump output circuit voltage is greater than 4.5 V for 0.5 s when the voltage should be 0 V.
P023F
The fuel pump power control module detects that the fuel pump current is less than 1 A and the fuel pump duty cycle is greater than approximately 50 percent for 1 s.
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 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.
On vehicles equipped with a high pressure mechanical pump on Direct Fuel Injection engines, the vehicle may continue to run even though the pump in the fuel tank is not operating.
Reference Information
Schematic Reference
Engine Controls Schematics (LHU) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left
Description and Operation
Fuel System Description Fuel System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the fuel pump turns ON and OFF when commanding the Fuel Pump Enable On and Off with a scan tool.
• If the fuel pump does not turn ON and OFF
Refer to Circuit/System Testing.
• If the fuel pump turns ON and OFF
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
5. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the G12 Fuel Pump. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
• If 5 ohms or greater
1. Ignition OFF, disconnect the harness connector at the Fuel Pump Power Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the Fuel Pump Power Control Module.
• If less than 5 ohms
3. Ignition ON, connect a test lamp between the supply voltage circuit terminal 1 and the low reference circuit terminal 2.
4. Verify the test lamp turns ON and OFF when commanding the Fuel Pump Enable On and Off with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the Fuel Pump Power Control Module.
2. Test for infinite resistance between the supply voltage circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the supply voltage circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the Fuel Pump Power Control Module.
• If the test lamp is always ON
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the Fuel Pump Power Control Module, ignition ON.
2. Test for less than 1 V between the supply voltage circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the Fuel Pump Power Control Module.
• If the test lamp turns ON and OFF
5. Replace the G12 Fuel Pump.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Fuel Pump Power Control Module Replacement Fuel Pump Power Control Module Replacement
* Fuel Tank Fuel Pump Module Replacement (NT7) Fuel Tank Fuel Pump Module Replacement (NT7)Fuel Tank Fuel Pump Module Replacement (NU6) Fuel Tank Fuel Pump Module Replacement (NU6)