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 Descriptor
DTC P0403: Exhaust Gas Recirculation (EGR) Solenoid Control CircuitDTC 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
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | P0107, P0641, P0532, P0452, | P0405 | P0641 | -- |
Sensor Signal | P0405 | P0405 | P0406 | P0404, P042E |
Low Reference | -- | P0406 | -- | -- |
EGR Solenoid High Control | -- | P0403 | P0403 | -- |
EGR Solenoid Low Control | -- | P0403 | -- | -- |
Circuit Description
The engine control module (ECM) tests the exhaust gas recirculation (EGR) system during deceleration. The control module does this by momentarily commanding the EGR valve to open while monitoring the signal circuit of the manifold absolute pressure (MAP) sensor. When the EGR valve is opened, the control module will expect to see a predetermined increase in MAP. If the expected increase in MAP is not detected, the control module records the amount of MAP difference that was detected and adjusts a calibrated fail counter towards a calibrated fail threshold level. The number of EGR flow test counts required to exceed the fail threshold may vary according to the amount of detected EGR flow error.
The EGR valve position sensor is monitored by the ECM. The 5-volt reference circuit, the low reference circuit, and the EGR valve position signal circuit are used by the ECM to determine the EGR valve position. The ECM compares the EGR Position Sensor parameter with the desired EGR Position parameter when the valve is commanded open or closed.
The ECM controls the EGR valve with a solid state device called a driver. The driver supplies the EGR solenoid with 12 volts that is pulse width modulated (PWM) through the EGR solenoid high control circuit. A ground path is provided by the ECM through the EGR solenoid low control circuit.
When the ignition switch is turned ON, the ECM records the EGR Learned Minimum Position. The ECM compares the EGR Learned Minimum Position parameter to the EGR Position Sensor parameter.
Conditions for Running the DTC
P0403, P0404, P0405, P0406, P042E
| • | DTC P0641 or P0651 are not set. |
| • | The Ignition 1 Signal parameter is between 11-18 volts. |
| • | The engine is cranking or running. |
| • | The DTC P0401 intrusive test is not active. |
| • | These DTCs run continuously when the above conditions are met. |
P0404
| • | The EGR valve is commanded open. |
| • | ECT is more than 75°C (167°F). |
P0406
| • | The EGR valve is not being commanded with a scan tool. |
| • | ECT is more than 75°C (167°F). |
P042E
| • | ECT is more than 75°C (167°F). |
| • | EGR Valve is commanded to 0 percent for 40 seconds after the EGR Valve has been commanded to 40 percent for 1 second. |
Conditions for Setting the DTC
P0403
The ECM detects an electrical malfunction in the EGR solenoid high control circuit or the EGR solenoid low control circuit for more than 20 seconds.
P0404
The difference between the EGR Position Sensor and the desired EGR Position is more than 9.5 percent for more than 120 seconds.
P0405
The EGR position sensor is less than 4 percent of the 5-volt reference for longer than 20 seconds.
P0406
The EGR position sensor voltage is more than 94.7 percent of the 5 volt reference voltage for longer than 4 seconds.
P042E
| • | The EGR position sensor is more than 5.5 percent of the 5-volt reference of the EGR Learned Minimum Position when the Desired EGR Position is commanded to 0 percent for 20 seconds. |
| • | The EGR position sensor is more than 40 percent and is steady for 5 seconds after a test failure and before the next test will be run. |
| • | The above conditions are met 4 times. |
Action Taken When the DTC Sets
DTC P0403, P0404, P0405, P0406, and P042E are type B DTCs.
Conditions for Clearing the MIL/DTC
DTC P0403, P0404, P0405, P0406, and P042E are type B DTCs.
Diagnostic Aids
Inspect for excessive deposits on the EGR valve pintle or seat. Remove the EGR valve and inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.
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
Important: If DTC P0641 or P0651 are also set, diagnose those DTCs first.
- With the ignition ON and the engine OFF, command the EGR from 0-90 percent. The EGR Position Sensor parameter should remain within 3 percent of the Desired EGR Position parameter through the entire range.
- 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 List.
Circuit/System Testing
Important: You must complete the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the EGR valve harness connector.
- Ignition ON, connect a test lamp between B+ and the EGR low control circuit. The test lamp should illuminate.
- Connect a test lamp between the EGR high control circuit and ground. Command the EGR valve from 0-90 percent and exit the EGR Solenoid Output Control. The test lamp should turn ON when commanded between 10 and 90 percent and turn OFF when exiting the EGR Solenoid Output Control.
- Ignition OFF, test for less than 5 ohm of resistance between the low reference circuit and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.
- Verify the EGR Position parameter is less than 1 percent.
- Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit . The EGR Position Sensor parameter should display more than 90 percent.
- If all circuits test normal, replace the EGR valve.
| ⇒ | If the test lamp does not illuminate, test the EGR low control circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If the test lamp is ON after exiting the EGR Solenoid Output Control, test the EGR high control circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If the test lamp is always OFF while commanding the EGR valve from 0-90 percent, test the EGR high control circuit for an open, high resistance, or a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground, short to EGR Control circuits or an 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for control module replacement and programming |
