C5 Anti-Pollution Fault - Intermittent

[Gozzy]

Hi to all on the forum,

My name is Mike and I own a 2001 Citroen C5 2.2 HDi Exclusive.

A few years ago I decided to bash out the CAT/DPF inside the exhaust, and turn off the DPF system using a Galletto cable and ECUSAFE. (i also emptied the Eolys tank underneath, next to the Diesel tank) For a long time all was well, until about 2 years ago when the car decides to throw up "Anti-Pollution" Warnings along with the EML+SERVICE lights on too, this often leads to limp mode. All this happens completely randomly, sometimes nothing for weeks, and then something for several days or weeks at a time. Limp mode is annoying, not to mention dangerous when on the motorways! I did have a Diesel Tuning box fitted, alongside a Piper cross performance Panel Air Filter, although I have now removed the tuning box as I thought it may have been causing these errors, although nothing has changed.

I have also blanked off the EGR pipe connecting into the air inlet chamber, and pulled off the vacuum pipe leading to the EGR valve and screwed a long bolt into the end of the vacuum pipe.

I have purchased a Lexia Kit, running on Windows XP Home 32-bit, I ran Lexia3 V358.01 and scanned for faults in all areas one at a time. Below I will list what I have come across so far:

In the Injection area, P0110 Permanent Fault, Inlet air temperature signal. CAN value not plausible.
P0402 Permanent Fault, Fault: Air Circuit. Amount of air measured lower than the setting
P0235 Temporary Fault, Turbo pressure signal. Short circuit to positive or open circuit or value too high
P0245 Temporary Fault, Turbo pressure. Turbo pressure measured too high
P0191 Temporary Fault, Fuel pressure regulator / sensor consistency. Consistency between fuel regulator current and pressure
And another which I forgot to get the code: Temporary Fault, Cat. converter upstream temperature signal (cat 1). Short circuit to + or open circuit

There was also mention somewhere in Lexia regarding low Eolys Fluid, now I do not know if this matters as I have turned the DPF system off (apparently!)

Can anyone shed any light on this one?

Thanks

Mike

[aramsay]

I had a very similar problem with my '02 2.2HDi.

The turbo boost control operates off the vacuum system in the car, and if there is a leak in this the turbo wants to go to full boost, so the ECU cuts the boost....i.e. limp mode.

In the engine compt. on the bulkhead on the N/S, and also one beside the battery, there are a load of vacuum valves and pipes. Check all the rubber unions for perished rubber, etc. that will leak air into the system.

Ideally you want something like a Mityvac vacumm tester to check the valves and around that section of pipes.

Good luck.

[Monkeyfeet]

Until someone more knowledgeable comes along I'd be going the overboost/ low vacuum route too.
If you can get hold of a gauge and measure the vacuum starting from the vac pump o/p it can help (100mB absolute last time I checked). You can then take a look at the solenoids too, maybe swap with the (unused) egr one to help rule out the vacuum cicuit.
Not sure if anyone else can advise here - can the turbo vane control "bellows" perish or the mech stick?
Also fuel pressure readings, red herring or further investigation needed?
Get the simpler things out of the way first

[Gozzy]

Many thanks for your help, I will look into this on saturday when i have the time. Btw running the car today to goto work and back with no errors or limp mode at all. I have looked under the bonnet earlier and i have spotted 5 solenoids, is this correct? I have traced vacuum pipes to both butterfly valves and egr valve. Am i correct in assuming the other 2 are for the turbo waste gate and the swirl chamber?

[Monkeyfeet]

That's it exactly. Took me a bit longer to work that all out..........
Let us know what you find.

[Gozzy]

How hard is it to trace the vacuum route to the turbo as this one seems to go behind the engine? And also tracing the swirl chambers vacuum?

To clarify, when checking these cacuum pipes am i inspecting the rubber joining ends only, or the whole (more rigid) vacuum pipes

[Monkeyfeet]

The line to the turbo does disappear round the back of the engine and downwards to the turbo I'm afraid. Fiddly to inspect. The swirl chamber is a little easier but still a fiddle. Had to change one out, had a broken plastic clip but they often perforate inside and can be a source of vacuum loss. Unrepairable but not too pricey though.
It's usually just the rubbery end bits that can deteriorate but worth checking the plastic lines for damage /squashing etc.

[aramsay]

In my case it was a few of the rubber joints/ends were split, and also the valve attached to the side of the air-filter box was leaking air.

Good luck !

[Johnny107]

Hi, I think I may have the same issue, just wondering what the outcome was?

[Stickyfinger]

MOT fail ahead.......for sale, spares or repair

[GiveMeABreak]

Hi, I think I may have the same issue, just wondering what the outcome was?

A) get the car on a diagnostic and post the codes up; you may just need to top up the additive tank, allow the vehicle to regenerate, have a stuck EGR valve that needs cleaning etc.,
B) Don’t do what the bloke who wrote the original
post did, apart from it being illegal to remove emissions devices and use on a public road, as Alasdair said, it’s a sure way to scrap your car.

His problems have likely surfaced because the injection ECU knows it’s about time to top up the additive system, which he took the silly decision to remove. As he can’t now top up any additive I suspect the ECU has engaged limp mode to reduce emissions and the continued use may be throwing up the other errors because of a conflict. In either case I suspect he has had to scrap it now because of the actions he took.

Additive really only needs to be done once or twice over the lifetime of the vehicle generally. There are also DPF cleaning kits and services widely available. This may not even be your problem, so a diagnostic is essential to troubleshoot.

[Harlequin]

I would say its vacuum and /or MAF/MAP related rather than dpf

[Monkeyfeet]

Hi Johnny,
Yes, it would be interesting to know. Anyway agree with Harlequin - It did sound very much like the usual perished / split vacuum pipes. Some seem to last longer than others. I know of a C5 mk1, same as mine, with dpf removed some 8yrs ago, still on original flexible hoses.
Double check those first. Only then move on to what they're connected to. I wouldn't start worrying too much quite yet.

[Hell Razor5543]

I had an intermittent Anti Pollution fault on my C5 Mk1. When Michel had a look he found a tiny hole in one of the rubber pipes about 1cm from the end. He trimmed the pipe back, reconnected it, and the fault has not occurred since.