Citroen C5Hdi Estate

[CitroenJohn]

Hi all, I have a 12 year old C5 Hdi Estate which was running ok until the engine management light/service light and the "anti-pollution fault" message came on. I have only had the car six months and it has been running very well, apart from a faulty speedo stepper motor, which I swapped sucessfully with the one off the rev counter, which then didn't work! Recently I dismantled the faulty stepper motor and repaired the broken pin which a little free gear wheel was running on, as per advice from a post on here or another online forum.

Back to the fault message - The car was due a service in 1200 miles so I changed the oil/air/fuel filters and the engine oil. This made the warning lights go out....until they came back on a few days later, only to go off again a few days later, only to come back on again, which is the present state of affairs. The car still drives ok, although now it is quite sluggish in the acceleration department until it has done about half a mile and then its ok. It's like a turbo suddenly kicking in and then its off!

I bought a hand-held code reader but it says my car will not communicate it. I don't have a lot of money to throw at this car by taking it to garages I don't know and so I thought I would ask one of the two members within reasonable distance of me who have Lexia machines (evilclive and rory_perrett) if they could help me out. Next problem; I couldn't Private message them on here as I am a new member and hadn't posted anything (this is my first post), and so one of the Admins said they would try to let them know I wanted to contact them. Since then I haven't heard anything, so I thought I would ask if any of you could help in some way or advise me as to what this fault could be. I spent 25 years as a self-employed Citroen mechanic and restorer but all this modern computer stuff that cars have these days does my head in!

Many thanks for reading and I look forward, hopefully, to reading your replies. Cheers chaps...John

[Lighty]

Your DL 16 diagnostic socket, shares the same fuse as the cig lighter, it's easy to blow the fuse for this & then get no communication.
Pin 16 should be 12 volts , see here
http://m.gendan.co.uk/article_3.html

[CitroenJohn]

Thanks Lighty, I will check that out as soon as I get a chance.

[CitroenJohn]

I have now checked Pin 16 and it is live with 12 volts. The cigar lighter is working but I couldn't find the fuse anyway as the owners handbook doesn't say which fuse covers it.

My fault reader will still not connect with the vehicle

It looks like back to square one It seems that I can now send PM's to other members (thank you Admin), so I will try to contact someone with a Lexia machine.

Any other suggestions gratefully received.

[BX]

Are you using a basic generic eobd/obd2 code reader without specific manufacturer selections . If so which injection system is fitted to the car Bosch or Siemens. Bosch works with generic code readers, Siemens generally doesn't

[jgra1]

John, I have an older c5 HDI,. my Anti Pollution Fault came on a year ago and my diagnostics (lexia) suggested an incoherence fault with the Mass Airflow Sensor (MAF)
I have the anti pollution warning most days, and the service light.. and 3 stages of limp mode..

1 when cold the engine is dangerously sluggish
2 after some warm up, engine is spritely but gives up at 3000 rpm
3 when hot after a good run, engine is back to normal power and often the lights and fault disappear..
its been this way for so long that I am used to it..

I will buy a new MAF some day soon..

it may be your issue...but it could be EGR or other problems maybe.. hopefully someone local can help I am not due in Bronte country in the next few days
John

[Peter.N.]

Very often the MAF only needs cleaning, it can get coated with oil which insulates from the airflow, a quick spray with carburettor cleaner fixed mine.

Peter

[xantia_v6]

so I thought I would ask one of the two members within reasonable distance of me who have Lexia machines (evilclive and rory_perrett) if they could help me out. Next problem; I couldn't Private message them on here as I am a new member and hadn't posted anything (this is my first post), and so one of the Admins said they would try to let them know I wanted to contact them. Since then I haven't heard anything,

Subsequent to your request, the admins have adjusted the board setting so that you (and all future new users) can send PMs to other individual members without a probation period.

Maybe you could try sending them direct PMs now?

[CitroenJohn]

Thanks for all your replies. I just took the car to the guy who does my MOT tests and he plugged his Delphi machine in for me.
There were five faults recorded, but the likely culprit was P0401 - EGR valve; negative deviation. Another was P0101; Air flow sensor circuit, at minimum limit

Member jgra1, who posted above seems to have a similar fault, as my car is sluggish when cold (and won't go up hills), but after about half a mile something happens and it suddenly accelerates normally. He reckoned it would be the EGR valve and wished me good luck! So my next step would be........

[Hell Razor5543]

Using some EGR Valve cleaning spray, but carefully.

[jgra1]

good news John

sorry my problem is the air flow sensor, not egr, but that and the egr seem to be possible for you..
I would remove the air flow sensor (a jubilee clip and two cross head or torx screws), and try and clean it with a spray cleaner.. when I do mine its quite obvious that its the problem and fixes it (the diagnostic has always pointed to this sensor) - my problem comes back after 2 days
I may buy a new sensor soon, as its getting slightly irritating after a year

I would clean or replace this first before the EGR? others may have better advice

John

[CitroenJohn]

Thanks John, I will take a look at things when I get chance. I know it's naughty but I read on another post that for some cars you can get a blanking plate to block the EGR off....

[Hell Razor5543]

You can, but that then could invalidate its emissions certificate, which might make it fail an MoT if they pick up on it. My C5 has just turned off the EML, which means the EGR valve might be coming unstuck. I will still give her a couple of shots of EGR valve cleaner though, but out in the open (as this can cause a lot of soot to blow through).

[CitroenJohn]

Well this afternoon I took the EGR valve off and gave it a clean inside, making sure that the valve opened and shut under vacuum pressure - it takes a fair bit of suck on a plastic tube to open that thing! It didn't seem very dirty but I cleaned it up the best I could. I didn't find it too difficult tricky to remove, although the new Citroen clamp which holds the cooling unit onto the EGR was pretty fiddly. The worst bits were repeatedly dropping allen keys down the back of the engine and then having to retrieve them!

After putting it back together I took the car out to get it up to operating temperature and then gave it the works with a can of Wynns EGR cleaner. There wasn't a lot of soot or smoke from the engine during this process but the fumes are really awful. I took the car out again and all seems to be well. The antipollution warning and EML didn't come on, but they have been on and off like a yo-yo lately and have been off for a few days anyway. I haven't found out yet if it still has the (non) acceleration problems when cold. I will probably have a go at the air flow sensor when I get the time. Just one bit of stupidity on my part......the Wynns aerosol comes with a little plastic tube to go in the nozzle - don't use it! On the first spray up the air intake this red tube was launched out of the nozzle by the pressure of the spray and shot down the air intake! What an idiot I felt....will this tube still be lodged somewhere down inside the air intake or will it do any harm? I don't fancy taking all that lot off to see if I can find it!

[CitroenJohn]

....and the next day, the warning lights are back on again.