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 P0403: Exhaust Gas Recirculation (EGR) Solenoid Control CircuitDTC P046C: Exhaust Gas Recirculation (EGR) Position Sensor Performance
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
EGR 5-Volt Reference Voltage | P0107, P0698, P2564 | P0102, P0401, P046C | P0405 | P0106, P0699, P2227, P2565 | -- |
EGR Sensor Signal | P0405 | P0101, P0405 | P0405 | P0106, P0401, P0699, P2565 | -- |
EGR Low Reference | -- | P0401, P046C | P0406 | -- | -- |
EGR MTR High Control | P0403 | P0401, P046C | P0403 | P0403, P2510 | -- |
EGR MTR Low Control | P0403, P046C | P0401, P046C | P0403 | P0403 | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine Running | ||||
EGR 5-Volt Reference Voltage | 0.98 Volts | 0 Volts | 0 Volts | 1.29 Volts |
EGR Sensor Signal | 0.98 Volts | 0 Volts | 0 Volts | 4.98 Volts |
EGR Low Reference | 0.98 Volts | -- | 4.8 Volts | -- |
High Motor Control | 0.98 Volts | 0.98 Volts | 0.98 Volts | 1.12 Volts |
Low Motor Control | 0.98 Volts | 0.98 Volts | 0.98 Volts | 0.98 Volts |
Circuit/System Description
The engine control module (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position , is sent from the sensor to the ECM through the EGR position sensor signal circuit. The ECM compares the actual EGR position with the desired EGR position when the EGR valve is commanded open or closed.
The EGR valve is controlled by the ECM through the EGR motor high control and the EGR motor low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. The ECM will pulse width modulation (PWM) the low control circuit to ground when EGR is desired. The lower the pulse width, the more the valve will open. The ECM will PWM the high control circuit to ground when the EGR valve is desired closed.
Conditions for Running the DTC
P0403
| • | The engine is running. |
| • | The EGR is not actively being controlled. |
| • | DTC P0403 runs continuously. |
OR
| • | The engine is running. |
| • | The EGR valve is actively being controlled. |
| • | The ECT is greater than 60°C (140°F). |
| • | DTC P0403 runs continuously. |
P046C
| • | DTCs P0401, P0402, P0403, P0642, or P0643 are not set. |
| • | The ECT sensor is greater than 60°C (140°F). |
| • | DTC P046C runs continuously when the above conditions have been met. |
Conditions for Setting the DTC
P0403
| • | The ECM detects an electrical malfunction on an EGR motor control circuit. |
| • | The above condition is present for more than 4 seconds. |
P046C
| • | The difference between the actual EGR position and the desired EGR position is more than 3 percent. |
| • | The above condition is present for more than 10 seconds. |
Action Taken When the DTC Sets
| • | DTCs P0403 and P046C are Type B DTCs. |
| • | Diesel particulate filter (DPF) regeneration is inhibited. |
Conditions for Clearing the DTC
DTCs P0403 and P046C are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EN-48565 EGR Test Harness
Circuit/System Verification
- Command the EGR valve to 30 percent with a scan tool. The commanded EGR position and the Actual EGR position should match.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Turn OFF the ignition. Disconnect the EGR valve. Install the EN-48565 between the EGR valve and the harness connector.
- Turn ON the ignition. Command the EGR valve to 50 percent and back to 0 percent. The EGR test harness lamp should turn ON between 10 percent and 50 percent, and turn OFF at 0 percent.
- After the motor control circuits have tested normal, the component to be replaced is dependant on which DTC is set.
| ⇒ | If the lamp does not turn ON and OFF, test both motor control circuit terminals D and F for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module. |
| ⇒ | If DTC P0403 was set, replace the EGR valve motor. |
| ⇒ | If DTC P046C was set, replace the EGR valve assembly. |
Repair Instructions
| • | Control Module References for ECM replacement, setup, and programming |
Repair Verification
- Install any components or connectors that have been removed or replaced during diagnosis.
- Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
- Clear the DTCs.
- Turn OFF the ignition for 90 seconds.
- Duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.
- Perform the Diesel Particulate Filter (DPF) Service Regeneration.
