P0403

DTC P0403

DTC DESCRIPTOR

DTC P0403
Exhaust Gas Recirculation (EGR) Solenoid Control Circuit

DIAGNOSTIC FAULT INFORMATION






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

TYPICAL SCAN TOOL DATA

EGR Position Sensor:

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 seconds.
- 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 malfunction indicator lamp (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.

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% with a scan tool, the commanded EGR position and the Actual EGR position should match

CIRCUIT/SYSTEM TESTING
Test the EGR motor High Control circuit and Low Control circuit for an open, short to voltage, short to ground, or for a faulty ECM.
- If the EGR motor High Control circuit and Low Control circuit test normal replace the EGR valve.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Exhaust Gas Recirculation (EGR) Valve Replacement
- Control Module References for ECM replacement, setup, and programming