C5 Limp home...

S

skp

Active member
Fellow Frogger
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Nov 22, 2010
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Location
Perth, Western Australia
I've a C5 in my workshop that goes into limp home after travelling at above 85Kmh for about 10 Km....
It remains alright doing stop / start stuff around the suburbs, but any prolonged higher speed travel triggers the "Engine Management Fault" warning - though this sometimes come up at slow speeds... the real trigger seems to be the ABS / ESP warning. As soon as it triggers, the engine looses 80% power. This is rather dangerous at intersections, and forget about overtaking entirely!

A computer search of the system revealed a faulty Steering wheel position sensor. This has been replaced, and has fixed a few other issues, but NOT the limp home issue. Despite the Engine Management and ABS mornings sounding and displaying, these DO NOT appear on the faults recording.... (??!!??)

Anyone got any ideas as to what might be triggering this?

Skp
 
Are the tyres all the same? Mismatched tyres, even the same type but one being worn and the other not can cause an ABS/ESP fault. That's common for all C5, but if it's an engine issue, then it would depend on which type of C5 you have. If it's a 2.2 6 speed, look at the intake flap motor down the front as that can drown in oil residue, throw a limp mode fault, yet apparently not record a fault.
 
What do you mean by limp home mode? Is the gearbox stuck in third default, or by limp home you mean a serious loss of power.
If it's the latter, and you find nothing else obvious I would replace the ABS unit.
As you know it cuts the power by limiting the throttle response when activated, which can only happen after a certain speed.

It seems when it's faulty it can be activated any time the brake is applied, seriously cutting the engine power. I pranged mine in the middle of an intersection because of it. A key off and wait, until the computer drops into economy mode sometimes may be the only way to clear it to get home.
Faulty it'll pass any Lexia solenoid operation tests without showing a fault. Take it for a drive with Lexia connected into ABS and see what transpires. Something I wish I'd done before parting with my C5. I don't think they can be repaired but you never know.
 
I have no skills to add a sensible comment ....

However ......

When I first got my 2005 C5 HDI it (intermittently):

- would sometimes go completely dead overnight (even on a fully charged battery)

- go into "emergency" (and/or?) limp mode .... everything shut down except the vitals to keep it moving.

I tried cleaning just about every connection under the bonnet I could find....unplugging and re-plugging connector blocks.

Checked for bad earths.....

Changed the battery....

Tried the various key in, window up, key out wait 30 secs, do a double pike with twist (etc etc)

And the problems still persisted, albeit less frequently.
Sometimes appeared once every few weeks.

And then it all stopped.
And has never done anything like it again and (touch wood) "appears" very reliable.

Citroens do that.
 
Shanadoo, I think that this makes most sense... Trying to follow the logic path of some of the electronic component interactions is frustrating, to say the least. It was not the stuck in third gear variety, just the loss of virtually all power when the ABS warning came on. I had similar problem with my own C5 a year or so ago, and that turned out to be a faulty throttle pedal position sensor....
This morning, after the "Limp' kicked in half way down the freeway, I stopped, turned everything off, waited for 30 seconds, pumped the brake a few times, restarted....... and everything was OK again. ( apart from "Engine Management Fault", but I think that is a separate matter...) This indeed leads me to suspect the ABS unit.
I'll let you know how I go.
skp
 
( apart from "Engine Management Fault", but I think that is a separate matter...) This indeed leads me to suspect the ABS unit.

Yes skp that's the way it goes, the time on the side of the road will probably get longer to reinitialize.
Mine eventually took until Economy Mode came on, 20min in most cases.

I reckon the engine management is probably because the system has recorded the retard throttle as a permanent fault. A download will probably come up with 'P0110 and P0101' among others. I would be ignoring all warnings till ABS is changed if your going there.

Stay Lucky Tony.
 
I'll continue this thread when i can.... We have had a fire in the workshop, so things are a tad messy on all fronts.
With some experimentation, I've discerned that when the ABS etc warnings come on, and we loose power, a shut down, stomp on the brake, restart, resets things back to full power. Engine management is still warning, but we do have power. I felt that the brakes were not quite right - just pressing on them while standing, they slowly sink. A bleed of the system is in order (air?), then a replacement of the ABS if no improvement. Replacing the EGR valve (whatever that is, wherever it is!!!) should do something for engine management - or so the computer interface leads me to suspect.
The problem with all of these computer interfaces is that they are ALL stupid and barely worth the trouble. ( see my rant in the "C5 mid 2000's .." Thread on page 1) They are just not informative enough. They SHOULD be able to say EXACTLY WHICH sensor is giving an aberrant signal. This narrows down the field of troubles enormously to a faulty sensor, or a fault upstream that can be deduced.

more at some point,

skp
 
The EGR valve is hard to get at, as it sits at the back of the engine somewhere near or under the turbo. It diverts exhaust gases back into the inlet manifold. It is supposed to do something useful, but mostly just seems to make everything oily. The actual vale is at the back, but there is a pipe that feeds the exhaust air back into the manifold at the top of the engine.

Erik
 
For what it is worth, I changed the rear swing arm bearings in a 2002 C5 hid & had to remove the magnetic sensor from the wheel assembly. After putting everything back, I kept getting brake fault warnings on the dash, bled the brakes several times etc, could not fix it. It turned out to be the way the hall effect sensor was mounted, it does not always seat in exactly the same way when it is put in. If it is not in exactly the right place, it does not pick up the signals from the toothed wheel on the back wheel assembly, so the computer brings up an error message. Fortunately in my case it did not go into limp mode. Once the sensor was in the right place, error messages went away. It is a long shot, but if all the wheel sensors are not reliably sending a signal to the abs unit, it can easily cause all sorts of problems with the computer.

Regards

agd123
 
I think I have the solution....
I started a thread on another side issue on the car - I had noticed a broken coupling on SOME DEVICE.. no idea what. "C5 Mystery lever".
I got a reply identifying the device, but more importantly, giving the back story of what it does and particularly when it DOESN'T.
The link to another thread gave the story of an identical series of problems and behaviour.
I've ordered the offending part, and we will see if this is the ultimate cure.
More later.
skp
 
To conclude this thread, Happily, I'm pleased to say - I have replaced a Swirl valve actuator. This was broken where it attached to the lever. How this could induce such dramatic power losses was beyond me.... The unit was replaced, AND a fractured air line joiner that fed it. The car now operates normally, with no ESP / ABS warnings and no loss of power.
It's been a long tortuous path to resolving this, but I have learnt quite a bit. Unlikely to ever use this knowledge again, unless helping someone on this forum....

For the backstory, read the Thread "C5 Mystery Lever".

Thanks to all.

SKP
 
My C5 has a different problem. I have a 2012 C5 with sat/nav which need updating. Who should I go to? I live in Coffs Harbour and also lose the radio sat/nav between Taree and Buladela, are these faults associated/ Any help appreciated.JohnVC
 
I hope my Xantia lives as long as I do. I don't want a C5.

Joh
 
Well, you are now a swirl valve actuator lever expert! That'll be handy! :)

Goodness. What amazes me sometimes with this level of complexity is that these modern cars work at all. Our Scenic started beeping at my daughter, "handbrake fault" on dash, refused to crank at all and the problem was slightly low battery voltage! Diagnosis method? We suspected battery having read so many threads here about odd things like that, and bingo, fixed!

Nice outcome, yours I mean.
 
Well done for tracking the problem down.

I need to investigate whether the 'Smart' engine has a 'Swirl' valve - could do, it's a similar era car (& French - sort of) & I have had the same issue with it intermittently going into limp mode. It's been @the fixers for 2½weeks now with no news :rolleyes:

If you think a Xantia's bad in limp, try a Smart, 3 cylinders & 80bhp on less than ½turbo boost - not pretty!

Baldrick
 
The Smart needs a cunning plan whereby a Benz/Smart forum is consulted.
Or post a few more times and then ask in the Toad Pond in case anyone else here has any idea.
 
David S said:
The Smart needs a cunning plan whereby a Benz/Smart forum is consulted.
Or post a few more times and then ask in the Toad Pond in case anyone else here has any idea.
Click to expand...

Probably damp matches. Buy a new box and keep trying. [sorry couldn't resist]
 
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