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 00: Fuel Pump Control Circuit Low VoltageDTC P0232 00: Fuel Pump Control Circuit High Voltage
DTC P023F 00: Fuel Pump Control Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Fuel Pump Voltage | P0231 00 | P023F 00 | P0232 00 | P023F 00 |
Fuel Pump Low Reference | -- | P023F 00 | -- | P023F 00 |
J420 Ground | -- | P023F 00 | -- | P023F 00 |
Circuit/System Description
The engine control module (ECM) supplies a high voltage signal to the fuel pump flow control module (FPCM) when the ECM detects that the ignition is on. The high voltage signal from the ECM to the FPCM remains active for two seconds, unless the engine is in crank or run. While this signal 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
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The FPCM records the operating conditions at the time the diagnostic fails. The FPCM stores this information in the Failure Records. |
Conditions for Clearing the DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
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
Engine Controls Connector End Views
Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the FPCM. Test for 1.0 ohm or less between terminal 16 and 47.
- Ignition OFF, reconnect the harness connector at the FPCM. Disconnect the harness connector at the fuel pump and sender assembly.
- Within 2 seconds of the ignition ON, test for 4 volts or greater between the fuel pump module voltage circuit terminal D and ground.
- Ignition OFF, test for 0 volts between the fuel pump module voltage circuit terminal D and ground.
- Ignition ON, test for 1.0 ohm or less between the fuel pump low reference circuit terminal A and ground.
- If all circuits test normal, replace the fuel tank pump module.
| ⇒ | If greater than the specified value, test the fuel pump voltage circuit and the fuel pump return ground circuits for an open/high resistance. If those circuits test normal, replace the fuel tank pump module. |
| ⇒ | If less than the specified range, test the fuel pump voltage circuit for a short to ground or an open/ high resistance. If the circuit tests normal, replace the FPCM. |
| ⇒ | If greater than the specified value, test the fuel pump voltage circuit for a short to voltage. If the circuit tests normal, replace the FPCM. |
| ⇒ | If greater the specified value, test the fuel pump low reference circuit for 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 |
