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Large MPVs -- Ford Galaxy / VW Sharan / SEAT Alhambra: => Mk3 Ford Galaxy / Ford S-Max => Topic started by: tallrob on October 22, 2020, 01:02:58 AM

Title: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: tallrob on October 22, 2020, 01:02:58 AM
Hi all, I need some help figuring out what I've done to my car after my second round of P242F DPF dealings with my 2007 S-Max 2.0 tdci (WA6)

A couple months ago I got the dreaded P242F DTC along with limp mode. I got another DTC P1335 telling me the EGR valve was stuck open, so I cleaned the EGR valve, did the MAF sensor trick and reset the code, followed by a long drive to activate a regeneration. It all worked out and the car was back to normal.

About three weeks ago I started getting the EGR code again, so I started monitoring the DPFE pressure. Over the course of the next week it steadily rose, but would not start a regeneration. I tried taking it on several long trips while monitoring the data, and it seemed to try a regen several times, but stopped just below 500º, and registered a failed regen attempt. Last week I got the P242F and P2463 DTCs again.

I couldn't reset it using the MAF trick, so this time I decided to remove the DPF and wash it with soap and water. It took a while but I got the water running clear and dried it for about an hour with a shop vac blowing in reverse. Just to be thorough, I also replaced the EGR valve, MAF sensor, DPFE sensor and air filter, cleaned the throttle body and changed the oil. I expected that to cover just about all the bases. I reset the EGR learned values and DPFE learned values and took it for a test drive.

The first thing I noticed was the DP_DPF pressure was extremely erratic, going from 0.9 to 25.0 kPa with values all over the place in a non-linear fashion. Also, the EGR valve appears to be always closed: EGRTP_V 4.46v EGRVP_V 1.00v EGR_TV 10.98% EGRVR 0.00% EGR_ERR -100% EGR_PCT 0.00% When I pull the plug on the MAF, the EGR values change for a moment, so the valve is functioning. It's just not changing at all while driving, whether the engine is cold or warm.

After driving for about 45 minutes on the highway, the DPF did a regen, climbing to almost 700º. The DPFE sensor however is still erratic so I have no way of knowing what the actual pressure is. I'm pretty sure this is still the original DPF after 240,000km, so I'm ordering a new one which should arrive soon. However I'd like to figure out the issue with the EGR and DPFE sensor before installing it.

I checked the turbo lines and everything looks pretty good. I'm going to replace the DPFE hoses and perhaps send this sensor back for exchange. I'll put the old sensor back tomorrow and see if the pressure reading stabilizes. I also thought of cleaning the intake manifold but at this point I'm just shooting in the dark.
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: SirDavidAlhambra on October 22, 2020, 08:39:04 AM
Is it possible the microscopic honeycomb mesh still had water in it which turned to steam and made it go funny perhaps
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: johnnyroper on October 22, 2020, 09:11:47 AM
Check the lines from DPF are clear as I have had the carbon build up restrict the pipework on a previous car causing erratic readings. A blow through with air line sorted it.

When did you check EGR feedback was it on idle or checking live data when on a run?
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: tallrob on October 22, 2020, 10:38:22 AM
Is it possible the microscopic honeycomb mesh still had water in it which turned to steam and made it go funny perhaps

I considered that, but I figured any remaining water should have been expelled after two hours of driving. It seemed slightly less erratic after the dpf regeneration, but still nowhere near stable. I'll try to have another drive and see if a second regen blows it out.
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: tallrob on October 22, 2020, 10:41:08 AM
Check the lines from DPF are clear as I have had the carbon build up restrict the pipework on a previous car causing erratic readings. A blow through with air line sorted it.

When did you check EGR feedback was it on idle or checking live data when on a run?

I blew the lines out when I had the DPF and DPFE sensor off. I'll check them again, though I doubt anything is plugging them. I've read about faulty new DPFE sensors, so I think I'll put the old one back on and see how it compares.

I was monitoring the live data during a drive. It never varied the under any driving circumstances.
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: tallrob on October 23, 2020, 11:56:44 AM
Update: Yesterday I swapped the old DPFE sensor in and reset the learned values. The pressure is now stable at 0.1 - 0.3 kPa at idle. So it seems it was a bad sensor. Also, the EGR valve started functioning at the same time, so the valve seems to be good.

HOWEVER, to to check the pressure after reinstalling the old DPFE sensor, I revved the motor up to 2000 rpms, to check the pressure, and suddenly the ABS light came on. Also got a large puff of smoke, which I assumed to be water remaining in the DPF. I stopped the live data stream to read the DTCs and got a new fault code P2263:72-27, Turbocharger Actuator Stuck Open, along with U0126 and U0401. I reset the DTCs and took it for a short drive, and the light came on again. Researching the P2263 it appears that it could be an electrical fault, and pointing to the MAP sensor, which could also have been the cause of premature DPF constriction. So I've ordered a new MAP sensor, along with a new throttle body, temp sensor and just for fun, a new DPF with I found for under 300.-  I doubt it's of the highest quality but it's not such a complicated part—we'll see.

If any of this sounds remotely familiar, please chime in. I'm crossing my fingers that I didn't kill my turbo while trying to fix all these other issues.
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: johnnyroper on October 23, 2020, 12:01:03 PM
Have you taken map out as they tend to block up with crap from egr?
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: tallrob on October 23, 2020, 01:41:32 PM
Have you taken map out as they tend to block up with crap from egr?

I took it out for a moment just to check compatibility of the new part. It didn't look too bad, a bit wet but not sludge up or anything. I did clean the entire throttle body when I changed out the EGR. Who knows, maybe I did more harm than good.
Title: Re: DPFE sensor erratic readings after DPF cleaning, new EGR valve stuck closed
Post by: mike wilson on October 28, 2020, 09:57:05 AM
I'm sure I've seen just activators on sale on ebay.  If you can't find one there, you could try turbodiesels.cc  Activators are not listed on the site but they are very amenable to talk to.