P0403

DTC P0403: Exhaust Gas Recirculation (EGR) Solenoid Control Circuit

Wiring Diagram:

Circuit Description
An Exhaust Gas Recirculation (EGR) system is used to lower Nitrogen Oxide (NOx) emission levels caused by high combustion temperatures. It accomplishes this by feeding small amounts of exhaust gases back into the combustion chamber. When the air/fuel mixture is diluted with the exhaust gases, combustion temperatures are reduced.

A electric EGR valve is used on this system. The electric EGR valve is designed to accurately supply exhaust gases to the engine without the use of intake manifold vacuum. The valve controls exhaust flow going into the intake manifold from the exhaust manifold through an orifice with an Engine Control Module (ECM) controlled pintle. The ECM controls the pintle position using inputs from the Throttle Position (TP) and Manifold Absolute Pressure (MAP) sensor. The ECM then commands the EGR valve to operate when necessary by controlling an ignition signal through the ECM. This can be monitored on a scan tool as the Desired EGR Position.

The ECM monitors the results of its command through a feedback signal. By sending a 5 volt reference and a EGR valve pintle position is sent to the ECM. This feedback signal can also be monitored on a scan tool and is the actual position of the EGR pintle. The Actual EGR Position should always be near the commanded or Desired EGR Position.

Conditions for Setting the DTC
- Engine is running.
- EGR valve circuit error.
- Ignition voltage is between 11 and 16 V.
- Engine time delay is greater than 0.5 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history Diagnostic Trouble Code (DTC) is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn OFF after four consecutive validation cycle in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- The DTC(s) can be cleared using the scan tool.

Step 1-6:

Troubleshooting