Good afternoon,

My 97 with 90000 miles on it has had some EGR problems lately. After the first incident, I removed the EGR and checked and cleaned it, replacing it after clearing the code. Maybe 1500 miles later the same code reappeared.
This time I bought a new EGR and cleared the code. After maybe another 1000 miles the light came on again. This time I ignored it and in due course the light went off. A couple of weeks ago the same code, P 0401 (insufficient
EGR flow) came back.

This aft I reset again. Friend John says he read somewhere that this code can be set by other than EGR problems - something about throttle position sensor and ???

Has anyone had this EGR code reappear several times as I have had? And did you determine the real cause?

Thanks in advance.

Regards,
Jack C.

Exactly what code number (DTC) was generated? There are several relating to the EGR.

The PCM module uses MAP (manifold absolute pressure) to test EGR flow. A common overlooked problem for DTC P0401 on a Series II 3800 engine is related to the PCV valve. So check to make sure you have the o-ring seal on the PCV valve. The PCV is located under the MAP sensor located on the right hand (passenger) side of the UIM plenum.