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 P0403: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit
DTC P0403 01: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit Short to Battery
DTC P0403 02: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit Short to Ground
DTC P0403 04: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit Open
DTC P0403 54: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit Temperature High
DTC P0489: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit Low Voltage
DTC P0490: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit High Voltage

### Circuit Description

Voltage is provided to the exhaust gas recirculation (EGR) valve by the ignition 1 voltage circuit through a fuse. Ground is provided to the EGR valve on the control circuit by a low side driver within the engine control module (ECM). The ECM monitors the voltage on the control circuit of the EGR valve to determine if a failure is present.

### Conditions for Running the DTC

• | The engine is running.

• | The ignition voltage is less than 16.5 volts.

• | The EGR is commanded ON.

• | The DTCs run continuously when the above conditions are met.

### Conditions for Setting the DTC

#### P0403

The ECM detects an open, short to ground or voltage on the control circuit of the EGR valve.

#### P0403 01

The ECM detects a short to voltage on the control circuit of the EGR valve.

#### P0403 02

The ECM detects a short to ground on the control circuit of the EGR valve.

#### P0403 04

The ECM detects an open circuit on the control circuit of the EGR valve.

#### P0403 54

The ECM detects that the internal output driver is over temperature.

#### P0489

The ECM detects an open or short to ground on the control circuit of the EGR valve.

#### P0490

The ECM detects a short to voltage on the control circuit of the EGR valve.

### Action Taken When the DTC Sets

DTCs P0403, P0489, and P0490 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0403, P0489, and P0490 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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 Verification

1. Engine running, observe the DTC information with a scan tool. DTCs P0403, P0489, or P0490 should not set.
2. Engine running, command the EGR valve to 100 percent. The engine should run rough or stall.
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.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EGR valve solenoid.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 2 and ground.

⇒ | If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

3. Connect a test lamp between the control circuit terminal 1 and the ignition 1 voltage circuit terminal 2.
4. Command the EGR valve solenoid between 5-95 percent with a scan tool. The test lamp should respond to the scan tool commands.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. Test for 2.6-4.6 volts between the control circuit terminal 1 and ground.

⇒ | If not within the specified range, replace the ECM.

6. If all circuits test normal, test or replace the EGR valve solenoid.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the EGR valve solenoid.
2. Test for 13-18 ohms of resistance between the control terminal 1 and the ignition 1 voltage terminal 2.

⇒ | If not within the specified range, replace the EGR valve solenoid.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Exhaust Gas Recirculation Valve Solenoid Replacement

• | Control Module References for ECM replacement, setup, and programming