OK, so here is the story...About 10 months ago, my check engine light came on. I read the code and got 401:EGR flow insufficient. So I mess around with the EGR and it seems to be fine. I play with my multimeter for a while and decide that I need to replace the DPFE sensor. I replace the sensor and have the battery disconnected to clear the computer. When I started her up again it seemed fine and has been fine since.

Last week, my check engine light came on again. I get the code read and it is the same thing 401. I think it is highly improbable that the DPFE sensor is bad again in only 8 months. I used a vacuum pump and messed with the EGR and it seems to be working fine. The engine still runs fine but at times seems a little sputtery. No stalling at idle or on a cold start.

When I read the VREF on the harness side of the DPFE sensor it was not between 4-6 Volts. Any suggestions as to what I can test or look at next. I don't want to have to replace the PCM because that costs like $150.
Any help would be greatly appreciated. Thanks!!

 

Pull the harness of the computer and check for corrosion those signal wires don't have much amperage so it's hard to push consistent voltage through them if they are corroded. Have you cleaned your MAF lately may help the sputtery feeling!