For 1990-2009 cars

### 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 Descriptors

DTC P064A: Fuel Pump Control Module Performance
DTC P1255: Fuel Pump 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 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.

### Action Taken When the DTC Sets

DTCs P064A and P1255 are Type A DTCs.

### Conditions for Clearing the DTC

DTCs P064A and P1255 are Type A 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.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component 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

#### 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 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.

2. Ensure that the entire undercarriage of the vehicle is clean, especially around the 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.

Control Module References for FPCM replacement, setup, and programming