Mondeo MK4 Whats your DPF Pressure?

[stimpy88]

Hi everyone, I have been having some problems with my diesel Mondeo (MK4, 2008). It had a problem with degraded oil, and that was fixed by an oil change. I think this may have been brought on by blanking my EGR.

However I noticed that the pressure (at idle) through the DPF had gone from its usual 2.2kP to over 4.5kP. I am not sure what to make of this, as I have just done a forced Regen on it, and it still reports 4.5kP.

One thing I did notice was that ForScan completed the Regen with a nice error warning saying that the regen had failed, but to my ears the regen went OK. The car did 2650RPM for about 10 mins or so, the idled back to normal. The car got very hot too, so I think that the error report was just a bug in ForScan.

So could any of you Mondeo diesel owners post your idle DPF pressure please? My DPF pressure at 2000RPM is just over 6kP, and idle is 4.5kP.

[FORScan]

4.5 KPa at idle seems to be too much. What is the differential pressure under a load?

One thing I did notice was that ForScan completed the Regen with a nice error warning saying that the regen had failed, but to my ears the regen went OK. The car did 2650RPM for about 10 mins or so, the idled back to normal. The car got very hot too, so I think that the error report was just a bug in ForScan.

We don't think it is a bug. For this vehicle FORScan does check result of regeneration analyzing DPF pressure after the procedure. Most likely it found the pressure is still too high. If you want, we can find out what happened exactly in that regeneration session (if you send us FORScan logs as described on Contact Us page).

By the way, are there any DTCs in the PCM module?

[stimpy88]

4.5 KPa at idle seems to be too much. What is the differential pressure under a load?

We don't think it is a bug. For this vehicle FORScan does check result of regeneration analyzing DPF pressure after the procedure. Most likely it found the pressure is still too high. If you want, we can find out what happened exactly in that regeneration session (if you send us FORScan logs as described on Contact Us page).

By the way, are there any DTCs in the PCM module?

Hi, and thank you very much for posting a reply.

I had to stop work on the car, as the wife needed it for work for a few days, but I'm going to let FORScan loose on it tomorrow. I noticed that the pressure was 4.5 to 4.6 at idle before the regen, and was the same after the regen finished, so the regen made no difference. I have also noticed that the average regen distance is now around 580Km, and i'm pretty sure this was up around 850Km or so last year. I'm starting to worry that the DPF has some kind of block in it, so I have taken it on the motorway and driven it hard in 5th gear for 45 mins, the car did not perform another regen during this drive.

The only thing that I have noticed about the performance of the car, was that while on my test drive, overtaking a lorry, the car was in 4th, and I floored it, and during the hard acceleration, the car kind of see-sawed, like I was lifting and lowering my foot on the throttle. The car has done this a handful of times in the past... Apart from this, the car seems to be fine, and has been reliable, and has only ever given me an engine warning last week, which was brought on by the car needing an oil change. The computer said that the oil was below suitable quality... My guess was that it wanted to do a regen, and as the change oil light had come on a few days earlier, it simply threw up the engine malfunction message, so I would take it to the garage for new oil, which I did, as well as treating it to a full flush out too.

After this, there are no other DTCs present, but I will know more in the morning, and will post back.

[stimpy88]

Well, not looking good after driving it hard...

The PCM has an error code P246B:00-6C - Vehicle Conditions Incorrect for Diesel Particulate Filter Regeneration

No matter what I do, the car tries to do a regen, then comes up with this error after it has finished. I had run a forced regen on it a few days ago, but just noticed that the car was running another one while I was giving it the test drive, so I pulled over and helped it complete the regen by keeping the revs at 2800 until the car finished, this took about another 10 mins. There was some soot on the road behind the car, but not too much. 20 mins later when I got home, I noticed the above fault code...

Anyone have any ideas what I should do next?

[stimpy88]

I have just had a thought... Could having the EGR valve blanked cause regens to fail? This is the only modification done on this car, and it was done 18 months ago!

Tried to attach my testdrive .fsl file, but nothing happens...

[william]

my kpa reading at idle is 0, when the car has idled for a few minutes the egr valve closes and the kpa reading for the dpf rise to 1 kpa.
under load the kpa reading rises to 14 kpa.

[FORScan]

The PCM has an error code P246B:00-6C - Vehicle Conditions Incorrect for Diesel Particulate Filter Regeneration

Hm... Are there any other DTCs, in addition to P246B?

Tried to attach my testdrive .fsl file, but nothing happens...

Just checked, FSL attachments show work... You need to select a file, then press "Add the file" button to upload the file, then submit the post.

[stimpy88]

Hi, and no, there are no other DTCs in any of the computers.

My conclusion so far is that the DPF is partially blocked, and maybe this may have been started by old age - the car has done just over 270000km. Or maybe, about a month ago, an injector split, and had to be replaced, so I wonder if unburnt diesel got in to the DPF.

I have taken the car to the mechanic to have the DPF cleaned. So in a few days, I should know more.

[stimpy88]

Well, got the car back, and they have had the DPF oven baked and cleaned. The mechanic said that the DPF was really dirty, and when it came back, it looked fantastic and he could see all the way through it! He also said that he took it out for a 40Km test drive, and thought that it was much better, and worked really well.

I drove it home, then took it on a small test drive, and hooked up FORScan and recorded my drive (link below), I noticed that the DPF pressure was still reading 4.5kP (at idle), but did not go up as high at high RPMs. It got as high as over 28kP,at 4500RPM, under load. The car does feel like it wants to accelerate faster as the RPMs increase, so it does do what the mechanic says.

The problem is that it is still reporting a differential pressure of 4.5kP at idle, why??? Any ideas???

Please see my testdrive data https://www.dropbox.com/s/rakg4w1th6t91 ... 2.fsl?dl=0

[FORScan]

The problem is that it is still reporting a differential pressure of 4.5kP at idle, why??? Any ideas???

Please see my testdrive data https://www.dropbox.com/s/rakg4w1th6t91 ... 2.fsl?dl=0

We would advise to first check the hoses from DPF to DPS and clean them if necessary. If this doesn't help, then measure the pressure using a 3rd party pressure-gauge (good workshop should be able to do this, odd thing your mechanic didn't suggest it). If the pressure is different than FORScan shows, it is either DPS or some problem with scaling this PID in FORScan (this can be checked on dealership scanner, we can do this if you will supply us with logs for your vehicle).