Depollution Blues

[dirkzobb]

Hi,
Had many XMs but new to 2005 C5 diesel - 2.2hdi - as a car it's nice to drive and I've sorted most of the quirks and glitches except for the dreaded 'Depollution System Fault'. Yellow light only comes on at idle/start-up - will go all day down the motorway with no show. Doesn't affect the performance at all. Fault code is P0402 then after a while adds P0400 then to top it all P1352 and the lovely yellow light Here's what I've tried/checked - vacuum valves for inlet butterflys both work OK as does the turbo valve (disconnected them and brought up expected faults). Thought the EGR may be stuck open so blanked it off - no difference, Changed the MAF - no difference. Does anyone know what the airflow g/s should be at idle? Mine's about 15.8 - 16.0 g/s. With engine stopped it still reads 1.52 g/s with both new MAF or old MAF - should it be zero? Can I zero it? Tried running with MAF disconnected - no effect on performance but new fault codes relating to air temp as you would expect but no P0402 - weird! It's driving me crazy - any help / suggestions appreciated.........

 

[coastline taxis]

check your mail ive sent you a message

[MikeLane]

Hi,

Had many XMs but new to 2005 C5 diesel - 2.2hdi - as a car it's nice to drive and I've sorted most of the quirks and glitches except for the dreaded 'Depollution System Fault'. Yellow light only comes on at idle/start-up - will go all day down the motorway with no show. Doesn't affect the performance at all. Fault code is P0402 then after a while adds P0400 then to top it all P1352 and the lovely yellow light Here's what I've tried/checked - vacuum valves for inlet butterflys both work OK as does the turbo valve (disconnected them and brought up expected faults). Thought the EGR may be stuck open so blanked it off - no difference, Changed the MAF - no difference. Does anyone know what the airflow g/s should be at idle? Mine's about 15.8 - 16.0 g/s. With engine stopped it still reads 1.52 g/s with both new MAF or old MAF - should it be zero? Can I zero it? Tried running with MAF disconnected - no effect on performance but new fault codes relating to air temp as you would expect but no P0402 - weird! It's driving me crazy - any help / suggestions appreciated.........

This isi the second time it's happened to my 2005 C5 1.6 HDi (96000 miles): The whistle blows, the "Engine" lamp lights and the message: "Depollution system faulty" comes on. The same thing happened every time I start the car. I panicked a bit as the car had been in for a related fault which turned out to be the switch operated by the filler cap. (Message this time: Risk of particle filter blocking) Anyway, by chance I went to open the sun roof with the ignition on but engine not started. Before it was fully open I spotted rain on the screen so closed it again. When the engine started, no whistle, no lamp and no message!

It recurred the other day and stayed on for a 300 mile round trip. It's almost due for a service but thought I'd try the sunroof again.

Ignition on, open and close sunroof, start engine. Result: no warning whistle, lamp or message!!!

[MikeLane]

Just found this very helpful company which will supply simply the DPF (or FAP) fitted to post 9/2004 C5 1.6 HDi engines (and several other PSA cars with the same engine) for £130:

 

http://www.cats2u.co.uk/34733/Diesel-Particulate-Filter/CITROEN/C5/1.6

 

or the complete CAT and DPF unit for £210

 

http://www.cats2u.co.uk/33950/Diesel-Particulate-Filter/CITROEN/C5/1.6

 

Their site has full instructions of what to check BEFORE buying a replacement unit and have emailed me with "how to split the CAT from the DPF if the vehicle still has the original part fitted".

[qman3428]

If you get the depolution error it can be a multiple of issues which causes it.

Cheap checks are:-

Disconnect the MAF, if it runs better suspect the maf is faulty.

Change the fuel filter, it blocks easily and gives a host of problems.

Changing the DPF filter by itself wont help as you probably need to refill the Eloys at the same tiime and you will then need to reset the ECU with a Lexia so it knows it has been filled

The error code above is the EGR and blanking it off wont remove the error, though it could fix the problem. If the EGR is defective, and reporting it is defective, then only replacing it, or removing it from the software, will get rid of the error light.

Using a lexia to diagnose the fault is only any good if you have the experience to understand the results. For example, mine said I had low fuel pressure but gave no reason why, there are a mutitude of possibilities but the main dealer identified the fuel filter was the culprit. So a quick change avoided the "trial and see" process of changing sensors.

[JM53 BEL]

I had DPF system fault on my 2008 (x7) 1.6HDi 110 vtr+ and it turned out the fuel filter was choked which caused fuel pressure to drop. Easy fix and worth trying first as it cost me £22 to put right. I have lexia 3 and fault codes were

p0087 & p0093 which comes back to be fuel pressure sensor and massive leak, so i checked for leak then thought what could cause drop in pressure which is when i came to conclusion choked fuel filter

[JM53 BEL]

Car runs sweet and has more power also.