C5 1.6 HDI - "Risk of particle filter clogging"

Hello everybody, I have a 2005 C5 1.6 HDI, which about six months ago started coming up with the error message "Antipollution system faulty". Every time this happened, the yellow warning light in the dash also came on. I read a lot about the error in this forum, and tried "driving like an italian", which cleared the error for some time.

However, the error came more and more frequently. In December, I got the "Risk of particle filter clogging" message. The "Service" light was lit at the same time.

I took the car to my my Citroen dealership, and they changed a sensor under the fuel filler cap, which they told me should tell the eolys management system when the tank was filled up with diesel. The "Antipollution..." disappeared, but the "Risk of ...." was still coming up every time I started the car. Then, after a couple of hundred miles, the "Antipollution" message also came back.

Took the car back to Citroen, they changed a new sensor (in the exhaust pipe this time). They also topped up the eolys tank, which they claimed were almost empty. Same thing happened, the "Antipollution" error disappeared for a while, but came back soon. The "Risk of particle filter clogging" was there all the time, together with the "Service" light.

I've now paid close to £800 and havebeen three times to the dealer. Now, they tell me that they need to change the particle filter, which they say is going to cost me close to £1000 (including labor). I asked if they were sure this would get rid of the problem, but they weren't sure at all. It might be the ECU, they said, and this would cost me at least another £1500.

I was really fed up, went home and pressure washed the filter. After starting the car, both error messages were still there. However, after driving for about 10 miles, the "Antipollution..." message disappeared, and I've now drive a couple of thousand miles without seing it.

The "Risk of particle filter clogging" is however still there, and it really annoys me. The most annoying thing is that I really dont know if it's something I can just ignore, or if I need to do anything. So, if there are any experts out there, could you please answer the following questions:

- Is there any way I can tell if eolys is added to the tank? My dealer says that the error message indicates that this is not happening, and that I risk clogging the filter completely if I continue to drive. If I bought a Lexia, would I be able to check this?

- Could it be that the dealer forgot to do some kind of reset after filling up the eolys? If so, is there any way I could reset this myself?

Any advice would be greatly appreciated! I'm actually very close to buying a Galetto and removing the filter altogether, but I would prefer to just get rid of the fault and keep the filter since I'm planning on selling the car pretty soon.

This may not be of any relevance to you but it is worth a mention. I recently px'd my 2002 C5 2L HDi for a 2008 C5 Tourer, again 2L HDi. 2 days ago the 'Depollution' light came on ( I suppose this is the same as your 'Antipollution'. It was checked out at my local dealers and the fault turned out to be, nothing to do with the DPF filter, it was, wait for it....the fuse box under the bonnet! This was correctly diagnosed and repaired via their diagnostic equipment. As I said, it may be of no relevance but worthy of a mention. Good Luck.

Hello everybody, I have a 2005 C5 1.6 HDI, which about six months ago started coming up with the error message "Antipollution system faulty". Every time this happened, the yellow warning light in the dash also came on. I read a lot about the error in this forum, and tried "driving like an italian", which cleared the error for some time.

However, the error came more and more frequently. In December, I got the "Risk of particle filter clogging" message. The "Service" light was lit at the same time.

I took the car to my my Citroën dealership, and they changed a sensor under the fuel filler cap, which they told me should tell the eolys management system when the tank was filled up with diesel. The "Antipollution..." disappeared, but the "Risk of ...." was still coming up every time I started the car. Then, after a couple of hundred miles, the "Antipollution" message also came back.

Took the car back to Citroën, they changed a new sensor (in the exhaust pipe this time). They also topped up the eolys tank, which they claimed were almost empty. Same thing happened, the "Antipollution" error disappeared for a while, but came back soon. The "Risk of particle filter clogging" was there all the time, together with the "Service" light.

I've now paid close to £800 and havebeen three times to the dealer. Now, they tell me that they need to change the particle filter, which they say is going to cost me close to £1000 (including labor). I asked if they were sure this would get rid of the problem, but they weren't sure at all. It might be the ECU, they said, and this would cost me at least another £1500.

I was really fed up, went home and pressure washed the filter. After starting the car, both error messages were still there. However, after driving for about 10 miles, the "Antipollution..." message disappeared, and I've now drive a couple of thousand miles without seing it.

The "Risk of particle filter clogging" is however still there, and it really annoys me. The most annoying thing is that I really dont know if it's something I can just ignore, or if I need to do anything. So, if there are any experts out there, could you please answer the following questions:

- Is there any way I can tell if eolys is added to the tank? My dealer says that the error message indicates that this is not happening, and that I risk clogging the filter completely if I continue to drive. If I bought a Lexia, would I be able to check this?

- Could it be that the dealer forgot to do some kind of reset after filling up the eolys? If so, is there any way I could reset this myself?

Any advice would be greatly appreciated! I'm actually very close to buying a Galetto and removing the filter altogether, but I would prefer to just get rid of the fault and keep the filter since I'm planning on selling the car pretty soon.

bump as i need to know as well

My understanding is that the message "risk of filter clogging" is because the filter is already partially clogged. Technically the system measures pressure drop across the filter and when it gets to a certain level brings up the message.
if the Eolys system has not been working correctly then the filter will block far earlier than the stated service time for a new or cleaned filter. It is possible to check the pressure drop across the filter with a Lexia however this does depend on the sensor being good and reasonably accurate if this is not the case then other related faults should be seen on a Lexia..
Something else to think about is that I have read (somewhere) that high back pressure caused by partial filter blockage is one of the reasons for the high failure rate of Turbo's on the 1.6.

cachaciero

Thanks for the answer. What I find strange is that after pressure washing the filter, the "Antipollution system faulty" message disappeared, but "Risk of particle filter clogging" is still there. Could it be that there is a fault code which needs to be reset after the washing?

Thanks for the answer. What I find strange is that after pressure washing the filter, the "Antipollution system faulty" message disappeared, but "Risk of particle filter clogging" is still there. Could it be that there is a fault code which needs to be reset after the washing?

The "Antipollution System Faulty" message is NOT specific to the FAP it is a generic message that comes up for almost any engine related failure. High levels of filter clogging would likely bring it up together with a filter blocked message, however it may also be that the high exhaust backpressure triggers something else. My best guess is that washing the filter has removed some of the blockage but not all / enough.

If the FAP system is working correctly then the filter gets filled up with an ash which is largely composed of cerium and burnt oil by-products. If the Eolys system is not working correctly then the filter will be blocked by heavy deposits of carbon.

Now while there are many reports of people pressure washing with success it may be that they have been cleaning filters that have little or no carbon in them, maybe the ash washes out easier than baked on carbon. This is speculation not known fact but it does seem possible to me.

I have also read of people having to put the complete filter in a high temp ovens (+600 C) to clean them also burning through with oxy-acetelyne to burn the carbon out. Again this is hearsay but if one needed to clean a carbon choked filter it does seem to me probable that this kind of treatment may be required.

cachaciero

Well, I'm really not very enthusiastic about going back to the dealer and fork out another £1000 or even more to get this sorted. If I buy a Galetto, flash the ECU and remove the FAP, do you know if the message will disappear, or does it need a reset with a Lexia?

Well, I'm really not very enthusiastic about going back to the dealer and fork out another £1000 or even more to get this sorted. If I buy a Galetto, flash the ECU and remove the FAP, do you know if the message will disappear, or does it need a reset with a Lexia?

Well I don't blame you, the ability of main dealers to adequately diagnose faults (NOT) has often been commented on in these forums. Your best bet might be to find someone with a Lexia close to you and get them to read all the fault codes and do a little diagnosing.

Really there is no way to be sure that removing FAP and the code for the FAP control from the ECU will cure your Anti Pollution message because we / you don't really know what is causing it, may be from the filter maybe something else.

If the Anti Polution message is permanent then the fault is permanent the message should disappear with a temporary fault after four start / run cycles.

cachaciero

I know this thread is long in the tooth right now but I have had long term anti pollution problems with my C5 mk3 tourer.
This culminated in the car cutting out and refusing to restart. The warning light still showed on the dash even with the keys removed. The battery was disconnected and then left off for a few minutes to reset the warning, and I at least managed to get the car going. In the meantime, I've found that the pollution filter can be removed and the engine ECU unit remapped to completely remove the problem for future. This with a claimed increase in performance, no detrimental MOT effects as the smoke will still be within acceptable limits. Cost of around £350. Given that Eolys oil top up at Citroen was quoted at £285 + VAT and then a replacement of the filter module at some extortionate cost, this is the way I'm going.

I can give a website address for the procedure but if you just Google for engine remapping particle filter removal, you'll find a dealer near you who does this.

I had the particle filter and engine remapping done yesterday.
The filter was choked almost full of really grotty ginger coloured ash. So much that it's a wonder the exhaust could manage to work at all.
Anyway, the filter itself is a honeycomb that can't be removed in order to clean it out. It's a chisel and hammer job and a lot of shoulder ache.
Almost half a bucket of rubbish removed.
Next the remapping was done. Took around 2 hours. The original code was saved, just in case......

So that done and the 176 bhp is now at 202. The low end torque is superb. So much so that at long last I can drive around town at 30mph in 4th gear and pull away from around 25mph in 4th.
Acceleration is fantastic and you can really feel the improvement. The engine runs quieter, the turbo lag is pretty much gone and you feel as if the cars got a new engine in it.
The best way to describe it is by saying the old unmapped engine with particle filter, now felt like I was dragging a trailer behind me.

I had the work done, all in, for a cost of £220 for the remapping and another £40 for chiseling out the filter and replacing it with new exhaust clamps.
The place I had it done at says almost every car with a particle filter can be done and Citroen - Peugot are easy as are many others.
Considering the cost of a new particle filter (don't even ask how much) this is a real bargain and the results are fan-bloody-tastic.

For those who are within striking distance and wish to have the job carried out for them at my nephews garage just call him on 07413591062. His name is Paul Fenwick. Tell him Lynn sent you.
He's at a garage on Armstrong Road, Peterlee, North East Industrial Estate. SR8 5AJ

Well, I'm really not very enthusiastic about going back to the dealer and fork out another £1000 or even more to get this sorted. If I buy a Galetto, flash the ECU and remove the FAP, do you know if the message will disappear, or does it need a reset with a Lexia?

If you go down that route, please let us know how you get on.

Our Peugeot 807 (03 vintage) threw up an "anti-pollution fault" type message 3 months after we got it. This was 2 years ago now so I'm struggling to remember the details. I think it was "Diesel filter blocked". After looking into it with my lexia clone it showed the readings from the differential pressure sensor (which measures the pressure loss across the filter) were stupid. £35 quid lighter in the pocket and a bit of crawling about under the car; all fixed.

[off topic warning]
I plugged the Lexia back in just before the new year, trying to work out why the Webasto/eberspacher doesn't work it told me nothing about it but did say the additive pump is open circuit
[/back on topic]

As an aside Lynzzer, presumably you have told you insurance company that your de-fapped car has been 'modified'.

Also, allowing a modern diesel to chug along at such low revs will put your DMF under extra stress, presuming your car is a manual of course

R

Have done around 600 miles since it was done. This included a return trip to London last weekend of around 250 miles each way.
I can see no great difference so far in consumption as they claimed would happen, and as I thought was apparent in my first few miles.
The performance is certainly a load better but I guess extra mph was a little too much to expect. I don't drive around in 4th gear at any speed under 30 mph really. It's just that if I drop back to below that for a short distance in normal town driving it pulls away no problem. It saves constant gear changing.
Given that it was done to overcome the pdf problem I think it was money well spent.

Insurance company? Hell no. I picked up a SP 30 only 3 weeks ago so why would I want to give them more to work with?

Just found this, what a great thread - at last, a real first-hand and up-to-the-minute story of heartache and victory.

I had the 'risk of blocked DPF' warning and the garage I took mine to was able to tell me the % of blockage. It was 80% when I first went in. I took it off and cleaned it out with hot washing-up liquid, then hot soda crystals plus an overnight soak and a good pressure wash.
Back at the garage it was measured at 19% blocked. Fault message erased and did not return.
Pity the car has now been scrapped for big-end failure!
RS