So the control unit and the actual Haldex units are seperate then? Cool I thought they would be. Glad it's the easier to get at bit thats fixed it. I cannot imagine how awkward the actual Haldex unit/Clutch unit would be to change
^ well I would have thought that the Clutch sensor would be easier and cheaper to fix, if that's the same thing you were referring to. My bro had his clutch sensor thing go bad on him and he changed it for around £20 (as far as I can remember) but if that was my problem it would have showed up in Vag-com but no errors in that area were detected.
I'm also thinking of replacing all the bushes since they've been on for over 2 years and they're probably worn in really bad, that's the next thing on my list :icon_thumright:
Oh and also maybe the new dieselgeek short shift as well :shrug:
Well took to it Russell automotive centre on Saturday and they diagnosed yesterday that the problem is the Haldex Controller. Told me the full price to replace it with the oil and filter would be over £800. Heart missed a beat when he told me that. Funny enough when I was driving the car to him on Sat I hardly had any probs at alll.
Now going to get a second hand unit and buy the oil and filter from GSF. Just need to get someone to fit it who knows what they are doing. Going to pick my car up today so I will see the diagnostic report.
Damn I want a good part for the car but over £800 is way too much!! Only porblem is that in buying a second hand unit you don't know if the porblem will reappear or not later. Might just wait and get uprated Haldex unit. Will all depend on how the car feels when I pick it up.
Humm, well it cost me around £600 for the uprated Haldex Unit from Awesome and I saw it as a worth while investment because it's either I get the uprated unit or replace it with the standard unit. The benefit of the first option is that it transforms how the car handles as well, giving it a much better feel through turns and bends, whereas the OEM Haldex will give you nothing and "might" sort out your problem.
I hope you get around to sorting it out mate, all in all I probably paid close to £800 with fitting (labour in London kills), hope you get things sorted. As I've mentioned above replacing to a new Haldex unit sorted out "my" problem I hope it can do the same for others here.
In other words their diags are good, but not the be-all.
To quote another person I have recently been having lengthy discussions about the problem who seems quite clued up....
"...the transient electrical faults will not show on computer scans"
Also found this thread from a long time ago. Read it and tell me if it sounds like the problem you had..
I think if this only occured at speed then it may indicate the haldex controller/unit.
So is the culprit most likely a busted Haldex control unit then?
Mine does it in reverse, kind of. I can get so far then it seems like the wheels jam and won't let me go back any further. And yes, I've checked there wasn't anything behind me. Happened once going forwards too, pulling out of a car park - the wheel started to seize then slipped. Wasn't fun.
Mine does the same thing rear locks on full or almost full lock. haldex throws an intermittent brake light switch failure, gonna change that and check hopefully that fixes it.
on mine the inside wheel locks up (thats what it sounds like. didnt get anyone to stand outside and have a look) Did not notice the ESP light flashing and symptoms are the same with ESP on / off , handbrake light on / off (handbrake on 1st click) both left and right turns. Previous owner said that Audi said that that is how the haldex works.
What i dont understand is how this would happen. if the 4wd is stuck on the on position then surely it should still allow the inside wheel and outside wheel to travel at different speeds? like a normal diff should operate on a rwd car? am i mistaken?
even if it was fixed and didnt allow the inside and outside rear wheels to travel at different speeds, then surely it should be the outside wheel that locks up since it is trying to turn faster than the inside wheel.?
OK, it's me here again.
Hate to say this BUT RE-READ MY POST 39 and THEN 25. Makes sense now does it ? maybe the so-called techy's need to be educated on how the haldex unit is not completely independant of the whole car. They cannot see that if you cannot talk - it's not that you cannot move your mouth , teeth, or tongue it could be your brain (or certain part of it).
Replacing the whole rear axle - are the having a laugh with you mate OR are they really just completely and utterly stupid ??????? That just shows complete lack of knowledge and pot luck (they think) approach and they still cannot see past their noses.
Will they guarantee it can't be anything else ?
Do you want to pay £XXXX on the car ? if that is what it is , I wouldn't. I'd sell it.
I'll say again. I know of one other person with the exact same symptoms (me included) and , for him, it turned out to be the abs/eps control unit - after changing the exact same thing they are advising you to do i.e changed the whole rear axle (changed the rear controller initially only).
Obviously haldex problems are fairly well known for this model, but unless someone can stand up with the exact same problems and say it was the haldex please step forward. I have a feeling their symptoms are not quite the same as ours.
I am living with the problem and waiting till I find another second hand unit and it may not even be that - It could still be one of the sensors I mentioned in my earlier posts !!
One final note about ....
"The techs at the garage told me that it's a problem they got often".
Can they forward your name and number to one of those people. Speak to them and ask them exactly what sort of problems were they experiencing - hear it from the horses mouth. Ask them what precise model/year audi do they have. What other work did they do at the same time. Was it fixed ? You don't know whether they went elsewhere after that. There are so many questions that come into my head especially when the techy's generalize the problem. As I said , it's true that 'generally' many do report haldex problems.
I see none of the people who mentioned having similar problems have come back with feedback/resolution. Just in case others in future look through this thread aren't really going to learn much !
yep, that's probably because no one has figured out what the problem is...
mine is still doing it 1 year on and 3 different garages have'nt figured it out either.... v annoying,.
This is a long but interesting thread, for my two penn'orth, the Haldex control unit should disengage the rear wheels for low speed turns. This is to prevent transmission wind-up. It does sound like this could be related to the problem people are having. There must be a sensor that sends a signal to the Haldex, when the car is close to full lock, maybe it is this that's the problem?
However the handbrake on a couple of notches should do the same thing, and it looks like this has already be tried, so maybe not.
latest update is that the join between the propshaft and rear diff/haldex type thing is 'falling apart' so i'll let you guys know if it helps with the symptoms...
My money is on a abs/ecu unit or one of the abs sensors. I am still trying to get a hold of a known good one and not reconditioned.
gotta say i loved reading this thread
i dont know anything really about how the haldex works and how the various sensors are tied into the correct functioning of it (apart from what i've read here) but if i had this problem i would be listening to thegoal007, replacing the haldex controller was tried and failed, so look elsewhere, although getting an upgraded controller is not by any means a waste of money im sure it is money that would of been better spent actually fixing the problem
when vagcom was plugged in to test sensors were you stationary?
if it was me i would have a mate doing the diagnostics whilst driving on full lock in a car park, it could be intermittant that wouldnt show whilst stopped?
also replace the whole rear axle? lmao
classic we havent got a scooby doo so just replace a big chunk of the car and hope to god it gets rid of the problem!!
just my personal thoughts of course, i hope you all get sorted soon!!
Well, When I had someone with the official cable & vagcom it was hapenning and all the figures looked ok and no errors.
Recently I bought myself a cheap cable and a registered version of vagcom 409. When I plugged it in and began to monitor in the ABS component section the abs logo appeared on the display showing it was disabled whilst monitoring and surprise surprise I could not get it to go wrong.
I then disconnected the vagcom and removed the fuse for the abs unit - but then the problem appeared just as though it was in ? the abs light lit up to show it was unplugged.
I need to go through the whole procedure again just to make sure the above wasn't a one off.
Meanwhile not one single error showing up anywhere on the car. So much for testing these cars with vagcom before buying one even after taking it out for a spin !
Intresting thread, And as said just seems daft to replace a rear axel, Does sound like a sensor or controller issue. Looking forward to seeing if there is anykind of definitive answer for this.
I am haveing the same/similar problem. Diffs locking on tight turns +can feel haldex disengage with a clunk when braking. I haven't got the time at the moment to fully diagnose the problem due to working away but on my vag com I have identified a comms error between engine ecu, haldex controller and the abs controller. The wiring between these is my first port of call as all sensors that feed these controllers are showing no faults (except intermittent brake light switch).
My thoughts are the coma errors are not allowing the controllers to
monitor steering angle and wheelspeed properly and is confusing the system thinging the wheel should be stright therefore the wheels are being told to rotate at the same speed which causes the inside wheel to slip then the haldex kicks in and tells the rears to kick in causing the jerk.
I noticed the problem is resolved if you complete the manouver at higher speeds. Which then Leeds me to the conclusion that the wheel speed and steering angle sensors are may rely on a singnal from each other to function. If the signal is to low on the wheelspeed sensors then the steering angle sensor is not active therefor not telling the ecu that the wheels should rotate at a lower rate on the inside than the outside. Haven't had the time to study the wiring diagrams but these are my thoughts on the problem.
Our symptoms do not sound exactly the same. Mine does not disengage when braking. I have no comms errors between anything. I have sometimes accelated into a tight right turn from standstill and it feels and probably looks to onlookers, that I am a learner driver about to stall the car as it jerks ! I would see the esp light briefly flashing as the car jerks. As the car straightens out it is OK.
And so far, no errors on vagcom at all. albeit shareware version - but it is a paid registered.
speeds sensors and steering angle sensors can be logged. although not quite sure what figures are good or bad (too low or too high?) when it comes to steering angles.
Hi, have you guys ever sorted this problem out? I know it is pretty old thread, but just bought the car and having these jerking problems. Situation worsen after haldex oil change.
No Ideas what to look for. Had scanned with vagcom and got all classic error codes:
16955 - Brake Switch (F): Implausible Signal
P0571 - 35-10 - - - Intermittent
01155 - Clutch
04-10 - Mechanical Malfunction - Intermittent
Would like to hear some solution to get it sorted! :blackrs4:
i have been living with my problem for about 2 years now - I just take it real easy on those tight slow corners. Every so often I try and narrow down the problem without luck.
One things most are saying is remove the haldex fuse -not 100% sure that really isolates it completely. After all people think the esp is disengaged completely when pressing the button, I gather that is not the case on 2001+ S3's
A recent post I read a guy fixed his problem by replacing the diff and controller. Others I've read: changing the haldex oil & filter & someone replaced the abs unit and one solved his by putting the pedal to the metal on full lock in a wet car park. Whether these people who simply replaced the oil & filer REALLY solved the problem or just said so in order to later sale is another story.
You don't say the year of your S3 you have. It appears you have vagcom - you may want to read this post and check your figures..
oh and I should say clear your errors just in case they are old ones. Apparently even the brake switch has an input into the haldex - so who knows. The above post by dnlcal - his last paragraph makes interesting reading too.
Thanks for reply on PM thegoal007!
My car is 2002 and has some other error codes not related to that! Good thing is that I have a friend with the same car and plan to ask haldex CU for a try, if it makes any difference.
I have read that haldex pre-charge pump is making serious problems with system, so it is worth to try out. But I am not sure if this is the case as I have rear wheel drive. Pump seems like a problem for those with missing rear drive...
I need to figure this out, as jerking makes me nuts.
A friend of mine had this problem with his S3, he changed the Haldex oil & filter and seemed to cure it. Not saying it will work for you but it's supposed to be done every two years or something so it's worth trying.
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Well I changed the oil and filter @ dealer 2 days before my first post on here.
Tried to do 360* this morning and felt it is gone, but then accelerated a bit, it happened again.
tried the handbrake 1 noch test - no jerking at that point, so haldex is turned off then..
Its one of 3 things.
Haldex oil and filter needed ( which has completely cured my problem)
Haldex controller is faulty
Or the small breather pipe on the haldex unit has split, letting moisture in which has mixed with the oil and damaged one or more of the clutched inside the unit - meaning a new diff/ haldex unit is needed!
Thegoal - do yourself a favor and stop thinking its something to do with a brake pedal switch or an esp fault because its simply not. To be fair in regards to you saying people might have just said its fixed for resale purposes is abit hypocritical, the fact you say you have had the (undiagnosed) problem for two years tells a pretty good story about how your car is looked after!
Take your car for a long drive down some country lanes mate, it does take a few miles to disapear after the oil has been changed, if it doesnt go then unfortunately its probably one of the above
So, having re-read the whole thread, there's not one common problem here but rather a selection of issues that give similar symptoms? Nice to know. The hand-brake thing doesn't work on mine, still lurches when reversing on full lock (seems to be worse steering to the left). I haven't tried taking out the haldex fuse, but I don't see that working either if the handbrake-up-a-notch thing doesn't work. The car's due in for a haldex service next month, so I'm interested to see if that makes any difference. If not, them I'm out of ideas again - I'm not looking to replace anything major since I'm wanting to sell the car, but it kind of annoys me that no-one seems to be able to actually diagnose the problem.
Like I said, haldex service is next month so hopefully it'll be sorted then.
I have found 4motion tehcnical documentation, will study thru it and let you know if any findings.
In case some of you read Russian - I can share pdf by email.
I've had the same problem before with my S3. Turned out to be 1 of the wheel sensors was foogard.
Quattro1, take note. Thank god you didn't give Sanj_c your valuable and 'quick to the point' advice. On the majority of cases it may well turn out to be what you say as we know there have been many varying haldex issues on these cars. I've read up so many stories over the last few years about haldex issues that they are never that straightforward.
With regards to my cherished car, I just don't like throwing away big (or small) money unnecessarily. The fact I only covered about 900 miles in the last year does not currently merit such a huge outlay without being sure of a fix. Especially when it just means I need to take it easy when doing those very tight 3 turns.
I've read a story of a guy with an S3 , same problem. Audi replaced his controller, then the diff and still had the problem. Turned out to be ABS ecu.....and my point is hopefully getting through.
My final point, I would like an understanding on the issue not have expensive guesses.