or Login >>         
C4 - DS4 Owners :: Forums :: Maintenance Tips ALL variant C4 C4 Picasso and DS4 :: Maintenance and Repair Tips and Procedures.

C4GP DPF System Failure - Solved.

Home   Forum Rules    Forum Help  Conversion Tools
Please Register to enjoy additional Member Benefits
Top Thanked Forum Posts: Today | Week | Month | Year | All time | Most Thanks Given: To member | By user
Author Post
Sun Aug 02 2015, 04:09am
Member No: #37329
Joined: Sep 12 2014
Location: Oxford
I own a 07 plate C4GP with around 120,000 miles on it, and apart from an airbag failure around a year ago, which Citroen repaired, it had been relatively trouble free.

However, some while ago I started getting DPF System Failure messages on my console, as well as the engine management indicator becoming illuminated. I have a friend who manages a small but good garage, and took the car there. He spotted that the EOLYS tank was not connected properly, and that they reconnected it.

Hopefully EOLYS would now be delivered to the fuel supply, and the issue would go away. It is worth mentioning also at this point that the car had, for a while, problems at low revs when just taking off, and oddly worse in reverse. Very juddery and shaky, but OK once going. I had attributed this to the semi-automatic gearing system needing recalibrating, for which there is a procedure elsewhere on this forum.

The issue didn't go away, and when the car started running a bit rougher, I took it to Citroen in Banbury. They told me the engine was 'misfiring' which was why it felt rough, and that the DPF was completely blocked, and that if I keep driving it, the car would soon go into 'Limp' mode, and I'd be back anyway.

They told me they could replace the DPF, EGR and differential exhaust gas pressure sensor for £1,200 there and then. Since I wasn't ready for a bill like that, I refused. They called me again and the guy told that '...he'd spoken to his manager...' and that they could now do it for £950, but it had to be done now.

I felt uncomfortable that they'd dropped the price by £250 at a stroke, and decided to do some research.

My car has 120,000 miles on the clock, and its resale value isn't that much, but I do need it to work. So I decided to have the DPF cleaned instead. I took my car to my friend's garage, and he took the DPF off and sent it away to DPF Clean Team in Hinkley - they use an ultrasonic cleaning technique which I don't understand, but is claimed to be effective. Two days later, it was back.

They told me it was definitely quite bad, but now it was at a level that would be expected from a new DPF. My friend fitted the DPF again, and no doubt the car was much better, especially the engine roughness which had largely gone.

However, the annoying thing was that the DPF warning light had not gone away.

Even after my friend had cleared the codes on the car, it kept coming back. He said he was unable to point to specific problem, but he did say it might be related to the differential gas pressure sensor - a device which detects the difference in pressure across the DPF, telling the ECU how blocked it is, and therefore whether to start a regeneration to clear it.

He said if that wasn't fixed, there was a danger that the DPF could simply block up again, and I'd be back to square one.

I decided to take a punt on this, and researched the cost of a new sensor. £45 new from GSF. I fitted it myself in an afternoon (it is located just behind the battery - that has to come out, as well as the plastic cradle that the battery sits in), then the sensors is visible.

The new sensors are much smaller than the one I replaced it with. I'm not a mechanic at all - this is the first car maintenance I've done for a lot of years, but it took be around 3h to do the job, probably should have been a lot less. One thing to be aware of is to make sure the two pipes which enter the sensor are connected the right way round - white marked pipe to sensor inlet with mark.

Once the sensor was fitted, I took the car for a test drive. The DPF System Fault error was still there, however I'd read that occasionally it takes a couple of drives for the fault to clear. Yesterday, after a long time, the fault cleared.

The car now has none of that judder that it had at low revs - although that didn't go away the moment I fitted the sensor; again, that took a couple of drives to clear. The MPG has shot up from around 42 MPG to around 50 MPG.

The engine runs very smoothly again, and - so far, touch wood, all is well. The other benefits I've noticed are that anything that is servo driven (brakes, steering) are way more responsive than they were before. Over time, the power must have gradually seeped away from these systems because of the fault (I don't know how), but now I would say the car is again a great pleasure to drive.

Thanks to this forum for the information needed to make this repair. In the end, it cost me £240 to have DPF cleaned, £90 for removal/refit, and £45 for a new sensor. £375 versus £950 - I'll spend the £575 on a holiday!
10 User said Thank You to apollojones for this Post :
 Dave_Retired. (02 Aug 2015 : 11:28) , BigJohnD (02 Aug 2015 : 11:32) , Jimux (06 Aug 2015 : 04:12) , Ballistic (19 Aug 2015 : 16:38) , devild46 (16 Dec 2015 : 10:56) , citroendoug (24 Feb 2016 : 13:13) , DeuxChevaux (21 Apr 2017 : 03:22) , spirohopper (03 Sep 2017 : 11:08) , wesso (26 Nov 2017 : 00:48) , Jammy_Jim (31 Dec 2020 : 11:26)
Sun Aug 02 2015, 11:27am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
Enjoy the holiday..... and the car again and thanks for taking the time to post your findings.
Sat Aug 15 2015, 04:37am
Member No: #41692
Joined: Aug 13 2015
Location: Gravesend
Was the juddering only in first gear and reverse? Sort of like you wasn't given it enough gas? That is what mine is like.also have the same problem with my pollution sensor fault.
Stuart Sauntson   
Thu Sep 17 2015, 12:02pm
I have some interesting observations which maybe of interest to others

I own a 2008 C4 Picasso VTR+ 1.6Hdi with 177,000 miles and a full service history

Recently it as been a bit of a nightmare with warnings on the centre console and EML illuminating periodically.

1, DPF risk of blocking
2, Diesel additive low
3, Depollution system Faulty

After some research on the interweb, I called Citroen and was presented with a quote much more than the car is worth. So I decided it could be time for some DIY mechanicals

Firstly I purchased a exhaust differential pressure sensor for £30 as I read this could cause the Depollution Fault.

I then ordered a seal kit for the DPF £36 from Citroen and once that had arrived I jacked up the car, place axle stands under and preceeded to remove the DPF. A very easy and simple process. Hardest part was removing the undertray. I then spent a while cleaning with hot water and using air pressure too remove a lot of orange dust, always wear a mask and googles. Once I had removed as much as I could, I flushed it out again with warm water and this time the water flowed through clear.

I replaced the DPF once it was dried and with the new gasket set and some exhaust sealant in the DPF - exhaust joint.

Finally I got some eolys 176 off eBay (5Litres for £85, 4 Litres Left) I jacked up the rear of the car and removed the tray and pouch refilled and replaced.

Finally having ordered the Lexia/Diagbox off eBay (£60) I plugged in the system, and carried out the following

1, read and cleared the fault codes, all codes related too items I Had changed, serviced
2, reset the eolys counter
3, reset DPF as a new Unit
4, re sync a keyfob after changing a low battery


So far no further warnings / lights have illuminated. The car is driving way more smoothly and ticks over very smoothly. I will update this if anything changes. Citroen wanted £75 just to read the fault codes.

If anyone is near too Cambridge and wants the fault codes read, let me know. The eolys fluid was very simple too top up. And the service parts ( sensor and gasket set) cost me £66

I hope this helps someone.. Any questions please ask
8 User said Thank You to for this Post :
 Dave_Retired. (17 Sep 2015 : 12:59) , FrankBullitt (17 Sep 2015 : 14:43) , BigJohnD (18 Sep 2015 : 07:02) , wilcovh (19 Sep 2015 : 13:05) , Ballistic (27 Sep 2015 : 03:47) , devild46 (16 Dec 2015 : 10:59) , volvoman480 (12 Jun 2016 : 02:29) , Jammy_Jim (31 Dec 2020 : 11:27)
Stuart Sauntson   
Sun Sep 20 2015, 05:41am

I am one very happy bunny, after removing and cleaning the DPF, the car is driving like a new one, very quite and smooth. Yet another wade of cash saved. Approx 1 hours work and all the EML warnings have gone. YIPEE!
3 User said Thank You to for this Post :
 polestarboy (20 Sep 2015 : 06:46) , BigJohnD (20 Sep 2015 : 07:39) , grumpyduck (10 Sep 2016 : 13:48)
Thu Apr 20 2017, 10:38am
Member No: #43860
Joined: Feb 24 2016
Location: Burnage South manchester
I know this post is a few years old but after some advice. Having had the DPF fluid changed in feb 2016 and had the regen done to rest ecu. I know the fluid should last 80000 miles approx so i know this is not low. Over past 3 weeks the " risk of particle filer blocking " warning has popped up along with yellow service light. I do mostly motorway miles at "legal" limit (300mls p\w) and this warning came on whilst doing 60ish mph.

Two days ago depollution and eml light came on as well. Called AA out and he removed and cleaned maf sensor reset ecu too. He did a regen as well but the blocking message did not go away.

Was instructed to do a 20\30 min drive at approx 4000rpm in low gear. I did this but still warning is there. I have no running problems no power loss but im stumped as what to do next. looking at changing the exhaust differential sensor as this seems easiest job first.

Great car but its pecking my head so any suggestions appreciated. Also does a lexia3 work on windows 7 ?
Thu Apr 20 2017, 11:45am

Member No: #19238
Joined: Apr 12 2011
Location: Cambridgeshire
It sounds like your DPF is now full - the EOLYS is an agent that needs changing at circa 80k (as you say) but the DPF is expected to be 'replaced' at 120k, exactly the mileage you are at. Thankfully, there are now plenty of companies out there that clean out DPF's to an almost-new position, find one locally and they will pressure the DPF clean. Be aware if you are driving that sort of mileage in the very near future the car will fail to start once the DPF completely full.
1 User said Thank You to FrankBullitt for this Post :
 nightshift247 (20 Apr 2017 : 12:10)
Thu Apr 20 2017, 01:20pm
Member No: #43860
Joined: Feb 24 2016
Location: Burnage South manchester
Thanks FrankBullitt. Do you know if the Lexia works on Windows 7? Found a place that cleans it out without taking off the car, is this the sort of procedure you are on about. Also found a mail order DPF filter for £119 but that's self fit or a full DPF inc the cat for under £200. Going to replace the pressure sensor as well.
Thu Apr 20 2017, 02:44pm
Member No: #27768
Joined: Oct 13 2012
Location: Hove
Lexia is old, you need diagbox really but lexia did come with diagbox & I run it on a Windows 7 laptop.
1 User said Thank You to rusky for this Post :
 nightshift247 (21 Apr 2017 : 07:48)
Sun Apr 23 2017, 05:27am
Member No: #43860
Joined: Feb 24 2016
Location: Burnage South manchester
My post/reply must have been kiss of death. Limp mode from 70mph is squeeky bottom time.
List of jobs to do is as follows:
Sort Two leaking injectors first
Buy fit new DPF/cat as nearly blocked
Buy and fit new Exhaust sensor ( have noticed a sensor on front slam panel with two pipes coming off the DPF is this the correct sensor ?)
Remove and clean EGR valve.
Get everything reset and fingers crossed.

Sat Apr 29 2017, 01:01pm
Member No: #45579
Joined: Jul 16 2016
Location: Ormskirk
Today I went to refill the Partical fluid sack/bag on my C4 GP HDi . put the fluid into the bag and had to quickly remove the fluid again... the bag has splits in it .......
I don't want to have to buy a fill bag at £150 + .. when I have just opened two bottles of PAT fluid ,,
Does anybody know if and where I can get a new or secondhand bag for it ??

Sat Apr 29 2017, 01:12pm
Member No: #27768
Joined: Oct 13 2012
Location: Hove
The bottle may be an option as there are 2 versions of the eloys container, a bag & bottle. I think only the bottle is refillable but I don't know if they are interchangeable or if the bottle is purchased empty.
1 User said Thank You to rusky for this Post :
 wesso (06 May 2017 : 01:08)
trev h   
Sun Apr 30 2017, 04:34am
Member No: #10864
Joined: Sep 11 2009
Location: kent/se london
Like you i had a split in my bag & wasn't prepared to pay £150 for a new one, i found a thread on another site & copied that, it was to use a hydration bag/camel pack the ones like runners use in their back packs, i bought a 2.5ltr one from a camping shop for £12 & put the fluid in that after cutting off the ends from the original bag & transferring them to the camel pack, i you look for my posts i did explain exactly what i did.
Fri May 05 2017, 05:08am
Member No: #43860
Joined: Feb 24 2016
Location: Burnage South manchester

Had the four injectors removed cleaned and re-seated for £180 + vat.
On collection of car was told turbo on its way out/gone.
booked car into a independent garage in cheadle stockport as they do the terraclean on dpf and engine. Said garage have rung me to indeed inform me that the turbo has gone.
So total price has shot up to £1250 for new turbo plus related pipes etc, dpf clean new pressure sensor clean and remove egr and supply and fit new timing-belt waterpump oil and filter change and ecu reset.

So fingers crossed when it comes back i should have many more years on happy motoring in a car i enjoy driving.
Mon May 08 2017, 12:22pm
Member No: #43860
Joined: Feb 24 2016
Location: Burnage South manchester
Update 2

Car's back all sorted except the daft warning of "risk of particle filter blocking" is still showing with the yellow service light.

Told the mechanic before I left and he said it should reset itself once driven. He checked again and there are no faults at all showing.

Just asking is there a way to reset this warning (as post by Stuart Sauntson above) or do I have to get a decent auto electrician to do this? As of yet I don't have Diagbox. Any reply welcome.
Go to page       >>   

Jump:     Back to top

User Colour Key:
Head Administrator, Administrator, Forum Moderator, Forum Moderator, Premier Member, Technical Expert, New C4 and DS4 Forum Moderators, Member