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 P0404: Exhaust Gas Recirculation (EGR) Open Position Performance
DTC P0405: Exhaust Gas Recirculation (EGR) Position Sensor Circuit Low Voltage
DTC P0406: Exhaust Gas Recirculation (EGR) Position Sensor Circuit High Voltage
DTC P1403: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit

### Typical Scan Tool Data

#### EGR Position Sensor

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: 0.60-0.80 Volts
Ignition 1 Voltage | 0.71 Volts | -- | --
5V Reference Voltage | 0.71 Volts | 0.01 Volts | 1.16 Volts
EGR Position Sensor Signal | 0.02 Volts | 5.00 Volts | 5.00 Volts*
EGR Solenoid Control | 3.78 Volts | 0.71 Volts | *
Low Reference | -- | 5.00 Volts | --
* Internal ECM damage may occur if the circuit is shorted to B+.

### 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.

The engine control module (ECM) monitors the position of the exhaust gas recirculation (EGR) valve through the EGR valve position sensor. The EGR valve position sensor sends a feedback voltage on the signal circuit to the ECM. The EGR position sensor voltage varies depending on the position of the EGR valve.

The EGR valve utilizes the following circuits:

• | An ignition 1 voltage circuit

• | A control circuit

• | A 5 volt reference circuit

• | A signal circuit

• | A low reference circuit

### Conditions for Running the DTC

#### P0403, P0404, P0405, and P0406

• | Ignition is ON or the engine is running

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

#### P1403

• | DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0171, P0172, P0300, P0335, P0336, P0337, P0341, P0342, P0351, P0352, P0445, P0462, P0463, P1671, P1672, and P1673 are not set.

• | The engine speed is between 1,950-2,600 RPM.

• | The ignition 1 voltage is more 10 volts.

• | The engine is operating in Closed Loop.

• | The engine coolant temperature (ECT) is greater than 60°C (140°F).

• | The intake air temperature (IAT) is greater than 15°C (59°F).

• | The manifold absolute pressure (MAP) is greater than 75 kPa (11 psi).

• | The mass airflow (MAF) is between 71-174 mg/tdc.

• | DTC P1403 runs 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.

#### P0404

The ECM detects a difference between the actual EGR position and the commanded EGR position.

#### P0405

The ECM detects that the EGR position voltage is less than 0.01 volt for more than 1 second.

#### P0406

The ECM detects that the EGR position voltage is more than 4.99 volts for more than 1 second.

#### P1403

The ECM detects the voltage on the control circuit of the EGR valve is low while the valve is not commanded or high while the valve is being commanded.

### Action Taken When the DTC Sets

DTCs P0403, P0405, P0406, and P1403 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0403, P0405, P0406, and P1403 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Description and Operation

Exhaust Gas Recirculation (EGR) 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Ignition ON, observe the EGR position sensor voltage parameter. The reading should be between the range 0.6-0.8 volts.
2. With a scan tool, command the EGR valve ON. The EGR position sensor voltage should fluctuate between 0.6-3.7 volts.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the exhaust gas recirculation (EGR) valve.
2. Ignition ON, load test for battery voltage between the ignition 1 voltage circuit of the EGR valve and ground.

⇒ | If less than B+, repair the ignition 1 voltage circuit of the EGR valve for a short to ground or an open/high resistance.

3. Ignition OFF, connect a test lamp between the control circuit of the EGR valve and B+.

⇒ | If test lamp illuminates, test the control circuit of the EGR valve for a short to ground. If the circuit/connections test normal, replace the engine control module (ECM).

Important: Voltage fluctuation is normal.

4. Ignition ON, With a scan tool, command the EGR valve ON. and test for less than 1 volt between the control circuit of the EGR valve and ground.

⇒ | If greater than 1 volt, test the control circuit of the EGR valve for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.

5. Ignition ON, verify that the EGR position sensor parameter is greater than 4.9 volts.

⇒ | If less than 4.9 volts, test the signal circuit of the EGR position sensor for a short to ground. If the circuit/connections test normal, replace the ECM.

6. Ignition ON, connect a test lamp between the 5-volt reference circuit of the EGR position sensor and ground.

Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.

7. Test for 4.8-5.2 volts between the 5-volt reference circuit of the EGR position sensor and ground.

⇒ | If less than 4.8 volts, test the 5-volt reference circuit of the EGR position sensor for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.

⇒ | If greater than 5.2 volts, test the 5-volt reference circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.

8. Ignition ON, test for less than 0.2 volt between the low reference circuit of the EGR position sensor and ground.

⇒ | If greater than 0.2 volt, test the low reference circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.

9. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit of the EGR position sensor and ground.

⇒ | If greater than 5 ohms, test the low reference circuit of the EGR position sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM.

10. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the EGR position sensor to verify that the EGR position sensor parameter is less than 0.2 volt.

⇒ | If greater than 0.2 volt, test the signal circuit of the EGR position sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.

11. If all circuits/connections test normal, test or replace the EGR valve.

### Component Testing

1. Ignition OFF, disconnect the harness connector of the exhaust gas recirculation (EGR) valve.
2. Measure for 6-10 ohms of resistance between the ignition 1 voltage and control circuit terminal of the EGR valve.

⇒ | If the resistance is out of the specified range, replace the EGR valve.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Exhaust Gas Recirculation Valve Replacement

• | Control Module References for engine control module replacement, setup, and programming