What’s a P0401 error code on a 2001 chrysler town and country?

EGR system fault (Exhaust Gas Recirculation)

– The ECM has detected too little flow on the EGR system

Probable Cause[s]

1. Blocked passage on EGR system

2. Failed EGR valve

3. EGR solenoid faulty

4. Failed EGR Pressure Sensor where applicable

5. Failed EGR Position Sensor where applicable

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In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticeable difference in RPM's with the EGR open

* Clean out the EGR valve and/or tubing to remove deposits

* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)

* Replace the DPFE sensor (with a good quality / OEM one)

* Replace the EGR valve