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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra Denali 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P025A

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 Descriptor

DTC P025A 00: Fuel Pump Flow Control Module Enable Circuit

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 ignition is ON.
    • Battery voltage is greater than 11.5 volts.

Conditions for Setting the DTC

The FPCM detects a fault on the fuel control enable signal circuit.

Action Taken When the DTC Sets
    • The engine will not run.
    • The ECM stores the DTC to memory.
    • The ECM will record the operating conditions at the time the diagnostic failed. The ECM stores this information in Failure Records.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Engine Controls Connector End Views

Description and Operation

Fuel System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

Important: Repair all U-codes before performing this diagnostic.

  1. Ignition OFF, disconnect the harness connectors at the ECM X1 and the FPCM.
  2. Ignition ON, test for 0 volts between the FPCM harness connector terminal 13 and ground.
    3. ⇒If greater than the specified voltage, test the fuel control enable signal circuit for a short to voltage.
  3. Ignition OFF, test for infinite resistance between the FPCM harness connector terminal 13 and ground.
    4. ⇒If less than the specified range, test the fuel control enable signal circuit for a short to ground.
  4. Ignition OFF, test for 1.0 ohm or less between the ECM harness connector X1 terminal 50 and FPCM harness connector terminal 13.
    5. ⇒If greater than the specified range, test the fuel control enable signal circuit for an open/high resistance.
  5. Reconnect the harness connectors at the ECM and the FPCM. With a scan tool, command the fuel pump ON. Verify that the Fuel Pump Command parameter displays ON.
    6. ⇒If the parameter does not display ON, replace the ECM.
  6. If all circuits test normal, replace the FPCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for FPCM or ECM replacement, setup, and programming