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 P029D: Injector 1 Leak
DTC P02A1: Injector 2 Leak
DTC P02A5: Injector 3 Leak
DTC P02A9: Injector 4 Leak

### Circuit/System Description

The fuel injectors are mounted in the cylinder head beneath the intake ports and spray fuel directly into the combustion chamber. Direct injection requires high fuel pressure due to the fuel injector's location in the combustion chamber. High pressure fuel is regulated by the fuel rail pressure (FRP) regulator, which is a part of the high pressure fuel pump. The engine control module (ECM) creates a feedback loop between the fuel rail fuel pressure sensor and the FRP regulator in order to maintain the desired fuel rail pressure. When the fuel injector delivers more fuel than is needed, indicating a stuck open or leaking fuel injector, the misfire counts will accumulate on that cylinder, the desired fuel rail pressure will not be able to be maintained, and this DTC will set.

### Conditions for Running the DTC

• | The misfire monitor is active.

• | The engine speed is between 1,520-6,000 RPM.

• | The engine load is less than 190.5 percent.

• | The DTCs run continuously within the enabling conditions.

### Conditions for Setting the DTC

• | The actual fuel pressure is more than 1,500 kPa (218 psi) below the desired fuel pressure and DTC P0087 is set.

• | The cylinder misfire counts are greater than 30 within 17 camshaft revolutions.

### Action Taken When the DTC Sets

• | DTCs P029D, P02A1, P02A5, and P02A9 are Type A DTCs.

• | The control module commands the engine to operate in the Reduced Engine Power mode.

• | The message center displays Reduced Engine Power.

### Conditions for Clearing the DTC

DTCs P029D, P02A1, P02A5, and P02A9 are Type A DTCs.

### Diagnostic Aids

A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder.

### 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

#### Scan Tool Reference

Control Module References for scan tool information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Verification

1. Clear the DTCs with a scan tool.
2. Engine operating, raise the engine speed to 2,000 RPM. Observe the DTC information with a scan tool. DTC P029D, P02A1, P02A1, P02A5, or P02A9 should not set.

⇒ | If a DTC failed this ignition, replace the appropriate fuel injector.

3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Direct Fuel Injector Replacement