machika A 4HX does have a variable nozzle turbine, controlled by a solenoid. Overboost on any HDi is uncommon [compared to the VAG ones] so what was the actual fault code or exact description? You've also got the full Eolys nightmare fitted; could it be something going adrift with that?
What is a 4HX?
I don't have details of the actual fault code, or exact description. I was only what I have said so far, i.e. excessive turbo boost.
The Eolys fluid was refilled at about 39K miles, so there should be no problem with the level of that. Other than that, I have not got a clue, except to say that the fault occurred on both occasions when I was accelerating from a slip road onto a dual carriageway, at about 70 mph.
|
|
I don't know if it is relevant, or not, but I had the particulate filter replaced only a week or so before this fault occurred.
|
|
|
machika
4HX is the most likely engine designation for this particular [DW12ATED] set-up. [It should be part of the VIN number that's visible through the base of the windscreen.]
Defaulting to "limp-home" and showing the K-light under hard acceleration is indeed consistant with an over-boost fault. If you've just had a new particle filter [£-ouch!] then that should rule out any possible regeneration issues; though the free-flowing new filter might have highlighted an existing but latent boost-control solenoid or system fault. If your garage is unsure about dealing with these, then maybe a good diesel specialist is one option.
|
Yes, 4HX is in the VIN number.
I don't know what the K-light is, the engine management system just reports an anti pollution fault and the engine loses power. Limp home is certainly the right term, as there is virtually no acceleration to speak of, although the car will very gradually pick up speed. I am a bit dubious about taking the car in to my usual garage, as he doesn't have a lot of diagnostic experience on C5s but, then again, he said that if I took it to the main dealer they wouldn't necessarily do any better and it would be likely to be a costly exercise.
|
machika
Sorry; K-light is PSA Group dealer-speak for an engine management warning. Can you re-set the system, after it defaults to limp-home, by switching the ignition on-and-off? Remote diagnosis on such complex and hotch-potch [at least 12 discrete versions] systems is rather tricky; but IF you've got the type with the turbo-control solenoid on the bulkhead - and if you've got a trusted garage - suggest to them that they visually check every inch of the hoses from the turbo's wastegate up to the solenoid valve and all hoses from that valve back to their source. The valve itself should be 15 ohms across it's two pins, apparently, and they've been known to stick.
Any more than that - or if you've got a different lay-out - then a diesel specialist is your best move. Deciding whether to replace any variable-vane turbo is one of the nastiest decisions to be faced with. Fortunately; I've never had to deal with overboost on a C5 [yet] so it'll be interesting to know what transpires.
|
Do you think it is possible that I am experiencing overboost on my Volvo S40?
The problem is described here;
www.honestjohn.co.uk/forum/post/index.htm?f=4&t=44...9
|
|
|
machika Sorry; K-light is PSA Group dealer-speak for an engine management warning. Can you re-set the system, after it defaults to limp-home, by switching the ignition on-and-off?
It doesn't normally re-set the system by switching the ignition on and off, but I have noticed it to start running normally sometimes after a rest but then the fault will recur again at some time, usually under fairly hard acceleration.
|
Not sure about excessive boost, but the antipollution fault on C5s is very common - often leading to 'limp home' mode. My one used to give the message quite often (but without 'limp home' kicking in) - but now it's been gone almost a year.
At the last service, dealer said I have an oil leak at the EGR valve - but only very minor. Perhaps under certain circumstances the EGR plays up and makes the electronics throw a wobbly.
Unfortunately I had the rare experience about 3 years ago of turbo failure on my 2.2. Fortunately it went under warranty and has been fine since new turbo was installed, but it took the dealer a week to diagnose the fault (I lost power big time and car wouldn't do more than 40mph flat out!)
Initially they ruled out turbo failure and played around taking off the exhaust to check for blockages etc, but finally they found that one of the turbo rotors had stuck while the other remained OK . They claimed they'd looked into one side of the turbo and it was fine but hadn't initially looked into the other side...........
What had caused the failure we don't know. The garage said lubrication to the turbo was fine. I have a suspicion, however, that another dealer who had been doing my servicing had filled the car with the wrong grade of synthetic oil. I think the 2.2 needs 5w 40 as opposed to 10w 40.
What you maybe could do is disconnect the battery - count to 10 - then reconnect. This can cure a multitude of sins on C5! (If you get an immobiliser fault and the car won't start after this lock the car with the key then re-open with the remote and all should be well.) You'll need to retune radio, set clock, auto wipers, speed warning etc as per handbook as well - but no problems.
Occasional 'Italian Tune Up' is good as well!
Graeme
|
Since my last post the car has spent two days with the garage that service it. The proprietor really had no idea what to look for initially and the local dealer couldn't help him either, as they had not come across a problem of excessive turbo boost before. Ultimately, the proprietor decided to replace a solenoid valve (one of two apparently) that controls the turbo boost, to see if it rectified the problem. He drove it about 20 miles afterwards, driving at speed for some of the time, as the fault always occurs when accelerating at 70 mph or above. The fault didn't recur, so I said I would pick it up and see how things went with it over a period of days. Well it didn't take long for the fault to recur as , when I was out in the car the next day (yesterday), the fault appeared again, just as I was driving along a local bypass.
I rang the garage as soon as I got home and they agreed to change the other solenoid. It was whilst on the way to the garage that the fault disappeared. It had never done this before and (fingers crossed), since then it has not appeared again. So, why it occurred in the first place I have no idea. The car has covered over a hundred miles since the fault disappeared, so I will just have to hope it is a good sign.
|
|
The fault has occurred twice since I last posted, includingafter the second solenoid was replaced. I began to feel that the garage I was dealing with were struggling to deal with the fault diagnosis, so today the car has been to the local main dealer. They have reported the problem as being corrupt software and the car has now had a software download to rectify this. I hope they are correct in their diagnosis and, if so, it will be money well spent. If not, it will be back to square one.
|
|
Well, the software download didn't work and a subsequent inspection of the car identified the likely cause as a split in a small rubber pipe, which was connected to an EGR valve. The car has been fine since the pipe was replaced.
|
">The car has been fine since the pipe was replaced.<"
All that at expertise, and it was a split pipe! Frightening really, one must doubt the competence of those who failed to diagnose the fault, have you paid the incompetents for their time?
|
">The car has been fine since the pipe was replaced.<" All that at expertise, and it was a split pipe! Frightening really, one must doubt the competence of those who failed to diagnose the fault, have you paid the incompetents for their time?
No, I haven't paid anything to the garage that normally services the car. I did doubt that he would be able to fix it from the start, as he never expressed any clear ideas, initially, on where he would start looking. He did rule out a spit hose, as the fault didn't recur immediately, after being cleared. He really hasn't got a great deal of experience of diagnostic work on C5s.
On one occasion the fault cleared all by itself and it was four days after that before it recurred. Also, it always recurred when the car had been run for the first time on the day in question. I once did a round trip of 160 miles or so, without the fault recurring. This included stopping twice for one to two hours on each occasion
The only thing I have paid for is the diagnostic check and software update.
|
|
suggest to them that they visually check every inch of the hoses from the turbo's wastegate up to the solenoid valve and all hoses from that valve back to their source.
They didn't listen then....
There's nothing an EGR can do to cause over-boost; that leak must have been in the turbo actuator's control hose or one that affects it.
Thanks for coming back with the fix. Glad they found it before they changed the turbo.
|
There's nothing an EGR can do to cause over-boost; that leak must have been in the turbo actuator's control hose or one that affects it.
I don't know where the EGR valve is situated, the technician having said it was strapped to the engine somewhere, just above the gearbox. He said the split hose could have caused a turbo overboost to be diagnosed, without there having actually been an overboost. He obviously has a lot of experience with HDIs.
The reason I eventually went to the main dealer, was that I feared I was getting involved in an expensive wild goose chase.
|
I also have a C5 2.2Hdi & thought i'd put in my 2 peneth.
As you had the particle filter replaced 1 week before the problem I thought it might be something disturbed when they changed it.
There are 2 steel sensor pipes attached to either end of the particle/cat filter.
One has to be disconnected from the particle filter when changed - the other stays attached to the cat.
Both pipes get moved a bit when wrestling the filter off the exhaust & join to rubber pipes as they enter the engin bay.
They obviously get warm during running as attached to the exhaust.
They end up on a pressure sensor module attached to the bulkhead which measures how blocked the particle filter is.
Thought one of these could possibly have got split.
No doubt this sensor has some influence over the amount of turbo boot available.
|
|
I discussed the replaced particle filter with the technician, so he was on the lookout for anything wrong with the associated pipework. It was nothing to do with those though.
|
Just had to say. I have a 2.2 Peugeot 406 which had the same problem had change the intercooler as it had a slight leak, also swapped the boost pressure control valve with the egr control valve as the are the same & was about to check & possibly change the turbo. But thanks to this posting I was able to trace it down to the diaphragm which controls the egr buttery fly in the inlet manifold which saved me a lot of time & cost.
So thank you for shearing this info with us!
|
|
|
|
|
|
