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%¹ |
EGR Position Sensor Signal | 0% | 0% | 100%¹ |
Low Reference | -- | 0% | -- |
¹ 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 more 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
Circuit/System Verification
- 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.
- Engine running, observe the EGR position sensor percentage parameter. The reading should be less than 1 percent.
- 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
- Ignition OFF, disconnect the harness connector of the EGR valve.
- Connect a test lamp between the ignition 1 voltage circuit of the EGR valve and ground.
- Ignition ON, load test for battery voltage between the ignition 1 voltage circuit of the EGR valve and ground.
- Ignition OFF, connect a test lamp between the control circuit of the EGR valve and B+.
- 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.
- Ignition ON, verify that the EGR position sensor parameter is less than 1 percent.
- Ignition ON, connect a test lamp between the 5-volt reference circuit of the EGR position sensor and ground.
- Test for 4.8-5.2 volts between the 5-volt reference circuit of the EGR position sensor and ground.
- Ignition ON, test for less than 0.2 volt between the low reference circuit of the EGR position sensor and ground.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit of the EGR position sensor and ground.
- 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 all circuits/connections test normal, test or replace the EGR valve.
Important: The test lamp is used to load the circuit and may not illuminate.
| ⇒ | If less than B+, repair the ignition 1 voltage circuit of EGR valve the for a short to ground or an open/high resistance. |
| ⇒ | 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. |
| ⇒ | 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. |
| ⇒ | 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. |
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 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. |
| ⇒ | 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. |
| ⇒ | 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. |
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the harness connector of the EGR valve.
- 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.
| • | Control Module References for ECM replacement, setup, and programming |
