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 rail pressure.

The ignition is ON.

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

DTC P025A is an A type DTC.

DTC P025A is an A type DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the FPCM.
2. Ignition OFF, connect a test lamp between the control circuit terminal 13 and ground.
3. Ignition ON, command the fuel pump ON and OFF with a scan tool ECM fuel pump output controls. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

⇒	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 ECM.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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