DPF issues 2012 C8 2.0 HDI

[parnell]

So i finally managed to get a diagbox working on the car and I think its the pressure sensor that is causing the P1490 and P1447 codes to come up - note the differential pressure sensor is reading ZERO despite the car running at 1216 RPM at 52 kmh...
Would be very interested to hear from other members what they thought though. thankyou!!

[parnell]

Next clue... I managed to get diagbox into live measurement mode (just ordered the nexas OBD device to make this easier going forwards) and here is what turned up.

Im confused -
1) the pressure sensor seems to work fine but yet when it threw a warning pressure differential was zero
2) I filled the EOLYS tank and reset the tank in the ECU and yet the measurements today indicate minimum additive level has NOT been reached AND 1444 Ml of additive remains in the tank (out of 1460 Ml) which is just mad - I put in 3L which is what Marc (and I believe him) told me is the capacity only two years and 5 thousand kms ago.

All assistance most thankfully received.

[parnell]

Well f*** it but i tried to give it the old Italian tune-up and the service light came on with limp mode engaging...then did a forced regeneration with the diagbox.... good news is that the differential pressure dropped a lot. Bad news is that the soot % remained the same (is that just calculated?). Im now considering doing a physical DPF clean ... car only has 132 tkms on it. Whats also frustrating is that the additive level hasnt budged either despite the forced regen...

[RichardW]

You've jumped on the back of someone else's thread, do you want me to split it out?

Roll back a bit, what issue are you trying to trouble shoot on what car?

Minimum additive level means low level, i.e. reached when the additive is nearly exhausted. There is no level measurement, it is only estimated - it looks like although the tank may have taken 3 litres, the factory programmed level was only 1460 ml, and when you perform the 'refill' procedure it just records this as the volume in the tank. This has dropped to 1444 ml, so used 16ml, which is probably not that far off for 5k km. There might be an option in Diagbox configuration to change it to the amount you put in.

I would caution against doing forced regens, this can melt the DPF if there is lots of soot present.

[parnell]

You've jumped on the back of someone else's thread, do you want me to split it out?

Roll back a bit, what issue are you trying to trouble shoot on what car?

Minimum additive level means low level, i.e. reached when the additive is nearly exhausted. There is no level measurement, it is only estimated - it looks like although the tank may have taken 3 litres, the factory programmed level was only 1460 ml, and when you perform the 'refill' procedure it just records this as the volume in the tank. This has dropped to 1444 ml, so used 16ml, which is probably not that far off for 5k km. There might be an option in Diagbox configuration to change it to the amount you put in.

I would caution against doing forced regens, this can melt the DPF if there is lots of soot present.

Sorry Richard , I wasnt aware of forum etiquette here - I originally thought the issue might be the pressure sensor - split it out if you think thats more consistent with the forum rules. Apologies to all.
Yes I didnt really want to do the forced regen. There is no soot at all coming from the exhaust - nor was there during the normal operation of the Citroen C8 that Im trying to fix.
The (reasonably persistent) error codes that I get are P1447 and P1490 - I thought it was a pressure sensor failure as reading zero pressure is just nuts. Now after reading more on the board I am more inclined to take out the whole DPF - although on the C8 its a long welded together contraption (at least its just horizontal under the car) so Im not sure how to use a pressure washer on it directly after I let it steep in some DPF cleaning overnight. Thanks for any support.

[mickthemaverick]

Just a warning, don't use a pressure washer on the dpf, you may damage it, just use whatever cleaner you choose and then rinse it out with a normal hose.

[RichardW]

Now split off into it's thread - no hard and fast rules, but it wasn't that easy to pick up what you were talking about!

Ideally you need to watch the dpf readings when driving to see what the pressure is doing. It could be a blocked pipe or a duff sensor. What is the diff pressure reading at idle and 3k rpm stationary?

[shtu]

You can use a chinese knockoff mityvac to test the differential sensor, or just suck and blow. The problem might be blocked, damaged, or missing pipework, though the sensors do fail. I had one that read 5mb difference with the engine off.

Forced regens = bad idea. They may burn off soot, but they don't burn off the ash and cerine left behind in the dpf, the only way to get rid of that is to wash it out.

As for pressure washer vs hose, I tried both, and found the hose more effective, with hindsight I would have also used an airline to add pressure to the water in a similar way to the commercial cleaning machines, but it's not essential, I managed fine with just water. Remember that you only need to wash it in one direction - back towards the engine.

I've been through all this palaver myself, so if you hunt in my older posts you'll find more detail.

[parnell]

Ok so Im back with some more readings today... thanks a lot to shtu and Mick for adding in their two cents. I will get to each in turn... here comes the readings at approximately 3.1k revs - so thats 27mbars whereas at idle the pressure is 0 mbars.
I tried to clear the codes using the diagbox but it said "clearing codes failed" without giving further reason.

[Citroennick]

Are you sure it has enough pat/Eolys fluid in it.!?

[parnell]

You can use a chinese knockoff mityvac to test the differential sensor, or just suck and blow. The problem might be blocked, damaged, or missing pipework, though the sensors do fail. I had one that read 5mb difference with the engine off.

Forced regens = bad idea. They may burn off soot, but they don't burn off the ash and cerine left behind in the dpf, the only way to get rid of that is to wash it out.

As for pressure washer vs hose, I tried both, and found the hose more effective, with hindsight I would have also used an airline to add pressure to the water in a similar way to the commercial cleaning machines, but it's not essential, I managed fine with just water. Remember that you only need to wash it in one direction - back towards the engine.

I've been through all this palaver myself, so if you hunt in my older posts you'll find more detail.

I ordered a new pressure sensor just in case although Im hopeful its functioning ok at the moment.

I didnt want to do the forced regen in all honesty - I just couldnt clear the codes and despite spending two hours driving yesterday the car went into limp mode and apparently this was the reason I couldnt encourage it to start a regeration cycle.

Would you recommend using a chemical dpf cleaner solution as well or just straight to the hose ? (Never mind this question your posts on the topic answered this thanks!) The DPF isnt a nice small bit of metal as on some other models but a single long welded together thing where the DPF itself is welded in - see attached picture - and it must be the portion between the two red lines so I guess Id put the fluid down the bendy end and have the tube held vertically bendy end up so let it steep into the dpf itself - which would be AWAY from the engine and not towards.

Very thankful for any help.

[mickthemaverick]

You can find all my thoughts on the subject of DPF cleaning if you read through this thread: viewtopic.php?p=672106#p672106

[parnell]

Are you sure it has enough pat/Eolys fluid in it.!?

I put in 3L of EOLYS and reset the counter 2 years and 5tkms ago - Im currently reading everything shtu posted on the topic of DPFs and trying to find if he has some magic about diagnosing the EOLYS pump.

When I did add the fluid the tank was almost empty - there have been no leaks at all on the car - which would be easy to detect as its kept in a garage with a clean concrete floor and that EOLYS stuff is very staining.

thanks for your help!

[parnell]

You can find all my thoughts on the subject of DPF cleaning if you read through this thread: viewtopic.php?p=672106#p672106

Just done with shtus posts - loved this one in particular (viewtopic.php?t=82712) - am convinced I will take the shagging thing off and physically clean it although the pressure reading of idle of 0mbar and at 3000 rpm of 27 mbar post forced regeneration doesnt sound too bad at all.

Am now going to go through yours - again - thanks very much - will also study the O Reillys garage youtube videos on the topic over the weekend.

I cant get a hold of Wynns DPF cleaner in Switzerland or Germany - is there another product members would recommend please consider the shape and length of the DPF on the C8 - see picture I posted earlier on this thread so I could imagine I would need around 7 litres of mixture.

[parnell]

After watching a huge number of those O'Rileys Autos videos on youtube - in particular the one where he is working on a Renault van and the DPF faults are triggered by a dodgy ambient temperature sensor in the wing mirror (!) I realise that I need to check again and look at all the fault codes so here we are:

U1213 - Fault in the vehicle speed information reveived by the CAN from the ABS or ESP ECU (which appears under the "Under inflation detection" and shows ALL tyre pressures at ZERO bars)

F5FF - UNexpected re-initialisation fault coming from the BSI (no further detail given)

P1490 we have covered before

P0215 Main relay : Local , Intermittent - Poor operation of the relay , the ECU is not being supplied as it should be {Engine status Cut or Stalled}

P050B Starting monitoring Local , Intermittent, Starting time too long