C5.2.2 GOING INTO LIMP MODE

[grandadkeith]

HI my c5 2.2 keeps going into limp mode after several miles.The journe,y begins with the check engine light on and the service light.After several miles the esp light illuminates and immisions light and the car goes into limp mode.I have had the car in my local garage,the first check showed turbo overboost.The fitter said I needed a new turbo,which I found hard to believe,as the car is running well with plenty of power before going into limp mode.Any help greatly appreciated.grandadkeith.

[Hell Razor5543]

The first (and, realistically, only) thing you should do at the moment is to put a Lexia system onto it. This can accurately read the car ECU faults and logs (generic readers cannot read many, if any, of them). Once this has happened you will have a much better idea as to what is going on. Here is the link to Lexia owners on the forum willing to help out;

http://www.frenchcarforum.co.uk/forum/v ... 19&t=29178

[GiveMeABreak]

What is the model, and how many miles have you done on it? How do you drive it - short journeys? Assuming it's a diesel, it may be that your car has not been regenerating the particulate filter and could be full of soot. It could also be low on additive - but as Hellrazor says get it a Lexia diagnostic kit first before you go paying out on things that may not be necessary. Most garages have a diagnostic reader - but not the bespoke Lexia which is essential for correctly interrogating your Citroen.

[mooseshaver]

When I had an 02 2.2 hdi I had these symptoms and the Citroen dealer wanted to replace turbo as car was getting a. Over post or boost to high fault.
Long story short it wasn't turbo but an electrovalve had failed. I know a pressure tester was used in the diagnosis and I think there is another electrovalve the same that can be swapped to see if fault changes.

[SaabC5]

All those symptoms on my 02 2.2Hdi pointed to a blocked DPF. Take if off, chuck a bottle of acidic wheel cleaner in it and then jet wash it out. Allow to drain and then reinstall. The fault will reset after approx 10 stop/start cycles.

[Monkeyfeet]

Hi Keith,
Agree with the other comments fully, you'll really benefit from a Lexia session. Replacing the turbo is way down the list for now. It all sounds complicated (it can be..) but on these cars it's the simple things that need checking first - the turbo is controlled by a vacuum circuit.
There's hoses running from the vacuum pump to various electrovalves (and a reservoir) and these need to be checked as they can cause the problems you describe, and can show up as an overboost fault.
If you can locate the hoses ( flexi black tubing, outside diameter about 1cm roughly)- check the hose ends for splitting etc.
There are other possible causes in the vac circuit but looking the hoses over is a good start.
Also let us know, is this a mk1 or 2? Can you supply those extra detail please?

[Sloppysod]

I would go with the above, my C5 Mk1 went into limp home mode, the first time I thought "oh Golly" (for the kids) this is going to cost me, booked it into the local Dealer and got a clean bill of health, no faults found - after resting it for a day it drove great - on the way to the garage
Other time limp mode had activated, I drove it steady holding it in third (Auto) for about 15 miles, problem cleared, and that would be the thing I would do first.

[cachaciero]

Swirl valve diaphragm rotted.
Check vacuum levels in this area as has been suggested by others. As far as turbo control is concerned low vacuum equates to max boost.
Much has been written on this forum over the years so a trawl through the archives should give you a good insite as to what to look for and how to do it.

[Peter.N.]

The pressure regulator on the back of the HP diesel pump can give that problem, it has a filter on it that can get blocked although I have never been able to successfully clear one but have fitted a secondhand regulator.

Peter