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 P0404: Exhaust Gas Recirculation (EGR) Open Position PerformanceDTC 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
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition 1 Voltage | P0405 | P0405 | -- | P0404, P042E |
Solenoid Control | P0402, P0404 | P0404 | P0404 | P0404, P042E |
5-Volt Reference | P0405 | P0404, P0405 | -- | -- |
EGR Position Sensor Signal | P0405 | P0405 | P0406 | P0404, P042E |
Low Reference | -- | P0406 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: 0-3% | |||
Ignition 1 Voltage | -- | -- | -- |
Solenoid Control | 100% | -- | -- |
5-Volt Reference | 0% | 0% | 100%* |
EGR Position Sensor Signal | 0% | 0% | 100%* |
Low Reference | -- | 0% | -- |
* 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 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
| • | DTCs P0112, P0113, P0405, P0406, and P0502 are not set. |
| • | The engine is running |
| • | The ignition voltage is between 11.7-16 volts. |
| • | The intake air temperature (IAT) is greater than 3°C (37°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 greater than 15 percent.
P0405
The ECM detects that the EGR position sensor percentage is less than 2 percent.
P0406
The ECM detects that the EGR position sensor percentage is greater than 98 percent.
P042E
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 P0404, P0405, P0406, and P042E are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0404, P0405, P0406, and P042E are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exhaust Gas Recirculation (EGR) System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool EGR Position Variance parameter while commanding the EGR valve to a 100 percent. The reading should be less than 15 percent.
- Engine running, observe the scan tool EGR position sensor percentage parameter. The reading should be less than 1 percent.
- 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
- Ignition OFF, disconnect the harness connector at the EGR valve.
- Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit terminal E and ground.
- Connect a test lamp between the control circuit terminal A and the ignition 1 voltage circuit terminal E. The test lamp should not illuminate.
- Command the EGR valve to 100 percent with a scan tool. Test for less than 0.5 volt between the control circuit terminal A and ground.
- Ignition OFF, test for less than 5 ohms between the low reference circuit terminal B and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal D and ground.
- Verify the scan tool EGR position sensor parameter is less than 1 percent.
- Install a 3A fused jumper wire between the signal circuit terminal C and the 5-volt reference circuit terminal D. Verify the scan tool EGR position sensor parameter is greater than 99 percent.
- If all circuits test normal, test or replace the EGR valve.
| ⇒ | 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. |
| ⇒ | If test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests 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.
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector of the EGR valve.
- Test for 6-10 ohms of resistance between the ignition 1 voltage terminal E and the control circuit terminal A.
| ⇒ | If not within the specified range, replace the EGR valve. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
