EGR Valve Position Sensor: Testing and Inspection

Operation:

Following is a short description of how the EGR valve pintle position sensor can be diagnosed by using a scan tool. The scan tool can also be used to compare the values for a normal running engine with the engine you are diagnosing.

DIAGNOSIS
The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM and to detect a fault if the pintle position sensor circuit is open or shorted. If the PCM detects and excessively low EGR Feedback signal voltage (pintle position feedback open or shorted), DTC P0405 will set.

The Linear EGR valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition positive or ground circuit. If an electrical malfunction occurs, DTC P0403 will set.

When the ignition switch is turned ON, the PCM learns the EGR closed valve pintle position. When the PCM commands the EGR valve closed, the learned EGR closed valve pintle position is compared to the Actual EGR position. If the Actual EGR position indicates that the EGR valve is still open, DTC P1404 will set.

When the PCM commands the EGR valve open, Actual EGR Position is compared with Desired EGR Position. If Actual EGR Position is 15% less than Desired EGR position when the PCM is commanding the EGR valve opened, DTC P0404 will set.

^ For diagnosis of DTCs refer to System Diagnosis / Diagnostic Tables / Diagnostic Trouble Code Tables. Testing and Inspection