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DTC P2635 (Fuel Pump Control Module)

DTC P2635 (Fuel Pump Control Module)

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 P2635

Fuel Pump Flow Performance

Diagnostic Fault Information

Circuit Short to Ground Open or High Resistance Short to Voltage Signal Performance
Control P0231 P023F P0232 P023F, P2635
Low Reference - P023F - P023F, P2635


Circuit/System Description

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module is active for 2 seconds if the engine is not in one of the modes for Crank (starting) or Run (driving). When this activity voltage is received, the fuel pump's control module closes the fuel pump's ground switch and supplies a varying voltage to the fuel pump module in the tank in order to maintain the desired fuel line pressure.

Conditions for Running the DTC


DTC P018B, P018C, P018D, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active.

DTC P0641 has not failed this ignition cycle.

Fuel pump control is enabled and the fuel pump control state is normal.

The system voltage is greater than 11 V.

The engine has been running for more than 30 seconds.


Conditions for Setting the DTC

This DTC sets when the fuel pump control module detects a predetermined fuel pressure performance degradation between the desired fuel rail pressure and the current estimated fuel rail pressure.

Action Taken When the DTC Sets

DTC P2635 is a Type B DTC.

Conditions for Clearing the DTC

DTC P2635 is a Type B DTC.

Diagnostic support

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 with direct injection engines and mechanical high-pressure pump the vehicle can be driven for a time even if the pump in the fuel tank is not working.

Reference Information

Schematic Reference

Engine Controls Schematics (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel System Description (LF1) Fuel System Description (LAU or LY7)

Electrical Information Reference


Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing


1. Verify that DTCs P018C, P018D, P0231, P0232, or P023F are not set.

Note

Do not replace K27 fuel pump control module based on DTC P2635 in History. DTC P2635 can be stored without a fault in the fuel pump control module. See Strategy Based Diagnosis .


2. If the DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

3. Ignition OFF, disconnect the harness connector at the G12 fuel pump.

4. Ignition ON, test for less than 5.0 Ω between the G12 fuel pump low reference circuit terminal B and ground.

5. If greater than the specified range, test the G12 fuel pump low reference circuit for a high resistance. If the circuit tests normal, replace the K27 fuel pump control module.

6. Ignition OFF, install a test lamp between the control circuit terminal A and the low reference circuit terminal B.

7. Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

8. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module.

9. 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 K27 fuel pump control module.

10. Perform the Fuel System Diagnosis (LF1 China) ; Fuel System Diagnosis (LF1 Except China) ; Fuel System Diagnosis (LAU China) ; Fuel System Diagnosis (LAU Except China) to verify proper fuel pressure.

11. If the fuel pressure is not normal, replace the G12 fuel pump

12. If all circuits test normal, replace the K27 fuel pump control module.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


Primary Fuel Tank Module Replacement (NA3, NE9, NF9) Primary Fuel Tank Module Replacement (NT7, NU5)

Control Module References for fuel pump control module replacement, setup, and programming