DPF pressure differential sensor

[sweeper]

So everyone loves an engine management lamp coming on and the vehicle going to limp mode, "help" we all say "i'm going to spend thousands fixing the mysterious issue" so my Viano did just this, my scanner would see the problem and erase it but couldn't tell me what it was. I called local indy who is full and couldn't fit me in for nearly two weeks, same for main dealer (I have to say, main dealer is my choice as they have all the inside info when it comes to diagnostics and likely the extra cost will be worth it) so I booked a mobile guy who came round a day or two later, I watched as he struggled to hook up the scanner and proudly told me it was the dpf and suggested various carbon cleaners by doctor carbon and similar names, or new dpf, however my experience (i have a back ground in vehicles and am VW trained from donkeys years ago and have been trained on Iveco and Detroit diesels, inc euro4-5-6 and mot3 and 5) i noticed one fault which was dpf differential pressure too low, and again my experience told me the vehicle will not regen if this sensor is reading wrong, for whatever reason, i looked up our fault finding chart for this fault and top of the list was pipes from dpf to sensor either blocked or inverted, knowing they weren't inverted I blew down them to see if they were blocked, they weren't blocked and I couldn't see any damage, so next in line was the sensor itself, so ordered up a new one fitted and I could now see the pressure differential on the icarsoft MBv3 that I have now purchased, this also allowed me to do a dpf regen and the fill level went from 137% to zero in a few miles, soot level remains at 2g/l, warning lights off and vehicle out of limp mode.
So what would have happened if i listened to the mobile guy, well I may have purchased a new dpf (it has done 331000miles) but the problem would have been back pretty soon due to the misdiagnosis, I recommend that anyone with engine faults uses the main dealer, honestly they have all the factory support and fault finding charts which take away the guess work, years ago we used a vw engine with edc for the first time, their fault finding charts were brilliant provided you followed them, mostly you could get to the route cause in 3 steps, but you do have to follow it, and in the order it showed, now since then things have gotten a bit more complicated with the use of adblu and dpfs but the principle is the same.
So fingers crossed my viano is ok now, i noticed my scanner doesn't allow me to tell the ecu it has a new sensor which may be an issue as it shows a pressure when not running but MB say they don't normally calibrate this sensor, so ill save my money and see what happens.

 

[M80]

Thanks for the write up,
I've the same Viano and have interest in what your iCarsoft is good for. Different models seem to have different functionality and the 639 doesn't seem to be top of their list for inclusions.
I'm assuming the V3 is the new pro?
I have the V2 and I've learnt not to trust all it tells me, their development is clearly ongoing and it may be that updates will rectify their using wrong units here and there.

 

[Botus]

DPF pressor sensor fault is a normal fault with Mercedes

On tractors around 2014 to 2019, NOx sensor faults are also standard - three iterations and three software updates, then the DPF actually starts to function as it was always intended... this fault should be FOC under the emission recalls (as it was faulty at time of manufacture) - but they don't want you to know this so the customer often pays >£1000. So I don't share your - use a dealer recco - they are lazy crooks. But don't go to any garage as they mostly know less about cars then your green waste bin man

 

[sweeper]

Thanks for the write up,
I've the same Viano and have interest in what your iCarsoft is good for. Different models seem to have different functionality and the 639 doesn't seem to be top of their list for inclusions.
I'm assuming the V3 is the new pro?
I have the V2 and I've learnt not to trust all it tells me, their development is clearly ongoing and it may be that updates will rectify their using wrong units here and there.

The V3 has limited function for the Vito/viano i cant use it to teach in new parts but it can do dpf regen and you can read lots of stuff, also disappointing was the function to calibrate the air suspension on my R class, the techs say it will and i've sent some log files for them to look into the issue as I asked before buying if it did, i have some new level sensors to fit and would like to do the calibration myself before fitting some adjustable links to alter the ride height, the V3 has function to teach in new parts on the R but I haven't the need to do this yet so can't comment on whether it works or not.

 

[sweeper]

DPF pressor sensor fault is a normal fault with Mercedes

On tractors around 2014 to 2019, NOx sensor faults are also standard - three iterations and three software updates, then the DPF actually starts to function as it was always intended... this fault should be FOC under the emission recalls (as it was faulty at time of manufacture) - but they don't want you to know this so the customer often pays >£1000. So I don't share your - use a dealer recco - they are lazy crooks. But don't go to any garage as they mostly know less about cars then your green waste bin man

I have had a few Mercedes and generally have repaired and serviced myself, I have a local independent specialist but haven't had very good experiences with him (ripped off with hand brake adjustment and I think kicked the tyres and changed the oil), i'd just bought the vehicle and as it was very high mileage and due a service, i thought id let him do it as i was short of time and get him to report any issues, he reported no faults despite the a/c not working and the bottom ball joints and front struts were shot, and he doesn't appear interested, he wouldn't even take on an injector replacement, the MB dealers have access to all the knowledge. all the service info and should be using it, plus you should have all back up/support that independents don't offer. My company vans were Merc for 10years or more, unfortunately once out of warranty the lease company would send them to back street garages, one time it was in for a week for steering noise, when all was lost they took it to Mercedes who fixed in 5 minutes as they knew the culprit (i wander how many steering racks have been changed due to a dry u/j in the steering column, quick bit of lube and good as new) they cured a rattle as they had the right info (honestly I could find where it was coming from, they knew instantly, they also cured vibration in my Vito sport using Mercs diagnostic charts which are comprehensive, if your Mercedes garage is getting it wrong have a word with head office, but i get any dealer can be a crook, if you have a Merc franchise it is worth holding onto, poor performance wont help you.
I had a bad experience with a Mitsubushi Main dealer who charged me for things on a service they simply did not do, they denied it of course but couldn't provide any evidence the work had been done, I could see it hadn't been touched and wished I had put in a little trap ( they said they changed the brake fluid but it was obvious they hadn't, they said they checked the valve clearances but is was obvious they hadn't had the rocker cover off.