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P0404




DTC P0404, P0405, P0406, or P042E

DTC Descriptors
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 P042E
- Exhaust Gas Recirculation (EGR) Closed Position Performance

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.






Typical Scan Tool Data






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 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.

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

P0404 and P042E
* The engine is running
* The intake air temperature (IAT) is between -3 to +120°C (+27 to +248°F).
* The DTC run 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.

Conditions for Setting the DTC

P0404

The ECM detects a difference between the actual EGR position and the commanded EGR position of more than 30 percent.

P0405

The ECM detects that the EGR position sensor percentage is less than 0.4 percent.

P0406

The ECM detects that the EGR position sensor percentage is greater than 99.6 percent.

P042E

The ECM detects the difference between the actual EGR position and the learned EGR position is greater than 34 percent.

Action Taken When the DTC Sets

DTC P0404, P0405, P0406, and P042E are Type A DTCs.

Action Taken When the DTC Sets

DTC P0404, P0405, P0406, and P042E are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics Electrical Diagrams

Connector End View Reference
* Engine Control Module (ECM) Connector End Views Engine Control Module (ECM) Connector End Views
* Engine Controls Connector End Views Engine Controls Connector End Views

Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Diagnostic Trouble Code (DTC) Type Definitions Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference
* Scan Tool Data List Scan Tool Data List
* Scan Tool Data Definitions Scan Tool Data Definitions
* Scan Tool Output Controls Scan Tool Output Controls

Circuit/System Verification

1. Ignition ON, observe the EGR Position Variance parameter while commanding the EGR valve to a 100 percent. The reading should be less than 15 percent.
2. Engine running, observe the EGR position sensor percentage parameter. The reading should be less than 1 percent.
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 of the EGR valve.

Important: The test lamp is used to load the circuit and may not illuminate.


2. Connect a test lamp between the ignition 1 voltage circuit of the EGR valve and ground.
3. Ignition ON, test for less than 0.1 volt between the ignition 1 voltage circuit of the EGR valve and B+.

• If greater than 0.1 volt, repair the ignition 1 voltage circuit of the EGR valve for a short to ground or an open/high resistance.

4. 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 ECM.

5. Ignition ON, with a scan tool, command the EGR valve to 100 percent and test for less than 0.5 volt between the control circuit of the EGR valve and ground.

• If greater than 0.5 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.

6. Ignition ON, verify that the EGR position sensor parameter is less than 1 percent.

• If greater than 1 percent, test the signal circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.

7. 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.


8. 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.

9. 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.

10. 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.

11. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the 5-volt reference circuit of the EGR position sensor to verify that the EGR position sensor parameter is greater than 99 percent.

• If less than 99 percent, test the signal circuit of the EGR position sensor for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.

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

Component Testing

1. Ignition OFF, disconnect the harness connector of the 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

Important: Always perform the Diagnostic Repair Verification Diagnostic Repair Verification after completing the diagnostic procedure.


* PSD SIE TITLE Error: SIE linked to empty Cell ID 139392
* Exhaust Gas Recirculation (EGR) Valve Replacement Exhaust Gas Recirculation (EGR) Valve Replacement
* PSD SIE TITLE Error: SIE linked to empty Cell ID 125195
* Control Module References Control Module References for engine control module replacement, setup, and programming

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