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 00: Fuel Pump Flow PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Fuel Pump Voltage Supply | P2635 | P2635 | P2635 | P2635 |
Fuel Pump Low Reference | P2635 | P2635 | P2635 | P2635 |
Circuit/System Description
The engine control module (ECM) supplies a high voltage signal to the fuel pump 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
| • | DTC P0191, P0192, P0193, 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 volts. |
Action Taken When the DTC Sets
DTC P2635 is an B type DTC.
Conditions for Clearing the DTC
DTC P2635 is an B type DTC.
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
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Important: Verify that DTC P0231, P0232, or P023F are not set as current or history before performing this diagnostic. If any of those codes are set as current or history, go to DTC P0231, P0232, or P023F.
- Ignition OFF, disconnect the harness connector at the fuel tank pump module.
- Ignition ON, test for 1.0 ohm or less between the fuel pump module low reference circuit terminal 2 and ground.
- Ignition OFF, disconnect the harness connector of the FPCM. Test for 1.0 ohm or less between the voltage supply circuit terminal 1 and the FPCM terminal 47.
- If all circuits test normal, go to Symptoms - Engine Controls to check for any intermittent symptoms and ensure that the fuel pressure is normal. If there are no symptoms and the fuel pressure is normal, replace the fuel tank pump module.
| ⇒ | If greater than the specified range, test the fuel pump module low reference circuit for a high resistance. If the circuit tests normal, replace the FPCM. |
| ⇒ | If greater than the specified range, test the voltage supply circuit for a 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 |
