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 CircuitDiagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
EGR 5-Volt Reference Voltage | P0107, P0401, P0698, P2564 | P0102, P046C, P0401 | P0405 | P0106, P0401, P0699, P2227, P2565 | -- |
EGR Sensor Signal | P0405 | P0101, P0405 | P0405 | P0699, P0106, P2565, P0401 | -- |
EGR Low Reference | -- | P0401, P046C | P0406 | -- | -- |
EGR MTR High Control | P0403, P046C | P0401, P046C | P0401, P046C | P0403, P2510 | -- |
EGR MTR Low Control | P0401, P0403, P046C | P0401, P046C | P0401, P046C | P0401, P046C, P0403, P2510 | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine Running, ECT sensor is less than 60°C (140°F) | ||||
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 | -- |
Circuit/System Description
The exhaust gas recirculation (EGR) valve is controlled by the engine control module (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. If the ECM detects an electrical malfunction on the control circuits, DTC P0403 will set.
Conditions for Running the DTC
| • | The engine is running for more than 0.5 second. |
| • | The EGR duty cycle is more than 10 percent. |
| • | DTC P0403 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects an electrical malfunction on an EGR motor control circuit. |
| • | The above condition is present for more than 30 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the DTC
| • | The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Special Tools Required
EN-48565 EGR Test Harness
Circuit/System Verification
Important: If you cannot duplicate the condition, 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.
- Command the EGR valve to 30 percent with a scan tool. The commanded EGR position and the Actual EGR position should match.
- Engine running, observe the DTC information with a scan tool. DTC P0403 should not set.
- 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 Records data.
| ⇒ | If DTC P046C is also set, diagnose DTC P046C first. |
Circuit/System Testing
Important: Perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Capture the information and clear the DTCs with a scan tool.
- 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.
| ⇒ | If the lamp does not turn ON and OFF, test both motor control circuits for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module. |
| ⇒ | If the lamp turns ON and OFF, replace the EGR valve motor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
