P1255

DTC P1255 or P064A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P064A
- Fuel Pump Flow Control Module Performance

DTC P1255
- Fuel Pump Flow Control Module Driver Over-temperature

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 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

* The FPCM detects an over-temperature fault.
* The above condition is present for greater than 12.5 milliseconds.

Action Taken When the DTC Sets

DTC P064A and P1255 are A type DTCs.

Conditions for Clearing the DTC

DTC P064A and P1255 are A type DTCs.

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.

Circuit/System Testing

1. Verify that DTC P0231, P0232 or P023F are not set as current or history.

^ If any of those codes are set, refer to DTC P0231, P0232, or P023F. P0231

2. Ensure that the entire undercarriage of the vehicle is clean, especially around the spare tire area where the FPCM is located. Clear all codes from the FPCM and test drive the vehicle. Verify that DTC P1255 or P064A do not set as current.

^ If DTC P1255 or P064A reset as current, replace the FPCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests