Contour Enthusiasts Group Archives Forums General Troubleshooting P0402

The proceedure for checking the EGR is posted by me below. You do not need to plug the vac hose for the EGR valve when you remove it. There should be NO vac when at idle. If there is a vac going to the EGR valve at idle, then the DPFE is very likely the culprit.

Good luck guys.

The p0402 code is excessive EGR flow. This code is used to signal a stuck open valve (particle lodged on the valve seat or clogged ambient port).

There are 3 parts to the EGR system. You have the Solenoid, the Valve, and the DPFE sensor. The PCM gives a Pulse Width Modulated signal to the Solenoid depending on how much EGR is desired. The solenoid then converts the electronic PWM signal to a vacuum and opens/closes the valve accordingly. At idle and WOT (Wide Open Throttle) no EGR will be requested.

If I were trying to figure this out, I would disconnect the hose off the valve; reset the codes (pull battery connection or appropriate fuses for 15 minutes,); then drive the vehicle with for a while and see if the code sets. The system will not be delivering any EGR flow if the valve is closed.

The system may then throw a p0401 code which is insufficient flow. If it gives the p0402 code I would focus on the valve or ambient port, if it gives a p0401 I would guess that the DPFE sensor is giving a bogus EPTZER reading and needs to be replaced.

One more thing, the strategy may have a two-trip counter embedded it, so you may need to drive the vehicle for a while, shut it off and drive again before any codes will appear.

ok. so I just finished testing the EGR Valve.

I placed a vacuum pump on it, zero vacuum while idling. check

Put 10in of vacuum, car stumbled - did not die, no loss in vacuum. constant stumble. check.

Released vacuum. Gauge went back to 0. Car idled fine.

Car did stumble a bit with no vacuum - gauge did not move when this happened. My mechanic says to replace the DPFE. He says its 98% that its the DPFE Sensor as its a VERY common problem with Fords in general he stated.

Took the DPFE Sensor off - about 20 minutes total time including diagnostics. Not as bad as I thought.

The DPFE Sensor casing is corroded - pieces of it are falling off with my fingers.

Anyway - I'm ordering the DPFE Sensor - What are your thoughts on my findings today with the vacuum gauge.

PS - All vacuum lines seemed fine. I couldn't find any cracks or anything.

Thanks

Do you think its possible to clean the sensor ?
I'd try spraying some intake cleaner - there's nothing to lose.

Tiv

where would I spray it?
it a sealed box - the only thing I could spray is the connectors.....

well, i only got the code last tuesday. reset the pcm, then the code came back. i drove around for a full day with the cel on....

so that's as constant as I needed it to be.