P025A

DTC P025A

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 Descriptor

DTC P025A
- Fuel Pump Control Module Enable Circuit

Diagnostic Fault Information






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 supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel pressure.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The serial data message from the ECM to the FPCM does not agree with the state of the control enable circuit voltage supplied from the ECM to the FPCM for more than 2 seconds.

Action Taken When the DTC Sets

DTC P025A is a Type B DTC.

Conditions for Clearing the DTC

DTC P025A is a Type B DTC.

Reference Information

Schematic Reference

Engine Controls Schematics (LS3) [1][2]Electrical DiagramsEngine Controls Schematics (LS7) [1][2]Electrical DiagramsEngine Controls Schematics (LS9) [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 5 Bow Lowered Switch (CM7)

Description and Operation

Fuel System Description (LS3 or LS7) Description and OperationFuel System Description (LS9) Description and Operation

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 Testing

Note: Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC resets before proceeding with the circuit system testing. If the DTC does not reset, refer to diagnostic aids.

1. Ignition OFF, disconnect the harness connector at the FPCM.

2. Connect a DMM set on the volt setting, between the enable control circuit terminal 13 and ground.

3. Ignition ON, command the ECM fuel pump ON with a scan tool. The DMM reading should be between 11.5-12.5 V.

• If less than the specified range, test the enable control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

4. If all circuits test normal, replace the FPCM.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Fuel Pump Flow Control Module Replacement Fuel Pump Flow Control Module Replacement

* Engine Control Module Replacement Service and Repair

* Control Module References Control Module References for FPCM replacement, programming and setup