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 provide 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
DTC P1404: Exhaust Gas Recirculation (EGR) Closed Position Performance

### 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 | -- | --
5-Volt Reference | 0.71 Volts | 0.01 Volts | 1.56 Volts
EGR Position Sensor Signal | 0.01 Volts | 5.00 Volts | 5.00 Volts*
EGR Solenoid Control | 3.78 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 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.

### Conditions for Running the DTC

#### P0403 or P1403

• | DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0300, P0335, P0336, P0341, and P0342 are not set.

• | The engine is operating in closed loop.

• | The ignition 1 voltage is more than 10 volts.

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

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

• | The manifold absolute pressure (MAP) is more than 75 kPa.

• | The engine airflow is between 71-174 mg/tdc.

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

• | The DTC runs continuously when the above conditions are met.

#### P0404

• | DTCs P0112, P0113, P0405, P0406, and P0501 are not set.

• | The startup engine coolant temperature is more than 10°C (50°F).

• | The engine coolant temperature is more than 65°C (149°F).

• | The ignition voltage is between 11-15.8 volts.

• | The intake air temperature (IAT) is between 3-120°C (37-248°F).

• | The air fuel ratio is more than 14.5:1.

• | The DTC runs continuously when the above conditions are met.

#### P0405 and P0406

• | The engine is running.

• | The ignition voltage is between 11.7-16 volts.

• | The DTC runs continuously when the above conditions are met.

#### P1404

• | DTCs P0112, P0113, P0405, P0406, and P0501 are not set.

• | The engine is running

• | The ignition voltage is between 11.7-16 volts.

• | The intake air temperature (IAT) is more than 3°C (37°F).

• | The DTC runs continuously when the above conditions are met.

### Conditions for Setting the DTC

#### P0403 or P1403

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

#### P0404

The ECM detects the learned position of the EGR pintle position is out of range.

#### P0405

The ECM detects that the EGR position sensor voltage is less than 0.16 volts for 10 seconds.

#### P0406

The ECM detects that the EGR position sensor voltage is more than 4.90 volts for 10 seconds.

#### P1404

The ECM detects the difference between the actual EGR position and the learned EGR position is greater than 10 percent.

### Action Taken When the DTC Sets

DTCs P0403, P0404, P0405, P0406, P1403, and P1404 are Type B DTCs.

### Action Taken When the DTC Sets

DTCs P0403, P0404, P0405, P0406, P1403, and P1404 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 of 0.60-0.80 volts.
2. With a scan tool, command the EGR valve ON. The EGR position sensor voltage should fluctuate between 0.60-4.00 volts for 3-5 seconds.
3. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the exhaust gas recirculation (EGR) valve.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit and battery 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 ignition 1 voltage circuit 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 and the ignition 1 voltage circuit.
4. Command the EGR solenoid ON with a scan tool. The test lamp should turn ON and OFF for 3-5 seconds.

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

5. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit and ground.

⇒ | If greater than 1.0 ohm, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.

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.

6. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.

⇒ | If less than 4.8 volts, test the 5-volt reference circuit 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 for a short to voltage. If the circuit/connections test normal, replace the ECM.

7. Verify that the EGR position sensor parameter is greater than 4.90 volts.

⇒ | If less than 4.90 volts, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the engine control module (ECM).

8. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool EGR position sensor parameter is less than 0.2 volts.

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

9. 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.

Important: The EGR must be near 20°C (68°F) in order for an accurate measurement.

2. Measure for 7.8-8.6 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