Haldex system confusion

Yeah :-( however my point was that I thought removing that fuse meant that the car would be effectively FWD so I was confused when it felt like the rear wheels were still being driven.

I tried a couple of hard stops on the wet roads with leaves and it didn't lock up or judder through the pedal - must try harder! I think we'll drive with caution until somebody comes up with a definitive solution as we don't want to spend ££££ on what was a £1,800 car. Ironic that it was bought as a winter/dog car with 4x4 and that's the only thing that's giving us problems
 
Has anyone got to the bottom of this issue. I have a 2002 BAM S3 my 2nd with this issue
Mine drags/locks the rear wheels when 3 point turning etc. hand break trick doesn't
Work for me but pulling the fuse for haldex controller does. It's had haldex oil filter new diff oil
New earth strap the rear diff plug checked and cleaned.

Also when You run the test in vcds with engine on it also solves it but
this is due to the controller being in diag mode and no awd
 
sadly seems to be luck of the draw....just changing the fluid and filter fixed mine.my filter was completly blocked with black crud .wonder if theres a way to blow the haldex through ???
 
Right I have been waiting in the wings and have now read all the posts.

So I have had this issue for months and have covered 20'000 miles without the fuse in. Note it is not fun when the car loses grip, so drive safe. it’s like a 200BHP 1980 front wheel drive hot hatch with no tranction control, if you’re old enough to have owned one of them.

My issue started after I had new tyres put on the front (Audi A3 2.0T Quattro 2006). I then did a 100 mile journey and noticed my ESP light flickering when pulling out of a lay-by. Thought nothing of it. After returning home, I then did another 100 mile trip no problems. parked my car and went to the office. Came out 8 hrs later turned the car on (no error lights) and drove away. Straight away I had clonking noise from the real wheels. Like Haldex was engaging them at the wrong time. The noise is there when driving in a straight line, turning, just moving it happens.

I changed the Haldex controller, this did not fix the issue. so removed the fuse, and it’s been like it since. Very annoying!!!!

After reviewing the Audi manual (get it from ebay for about 7quid) there are a number of tests all with fuse in:

1. Handbrake lift it up one notch - Yes this stops the noise
2. Pull away in second gear - Yes but as soon as I turn a corner or the front wheels slip noise comes back
3. Drive along and press the brake at the same time - I will be doing this, this weekend.

I had an ex Audi guy check the car over, he noticed the Haldex oil had grey tints in it, and stated the Haldex inside was chewed up. After much searching I found my car had the Haldex oil (this was by tracing the history back to the original owner) changed at 20'000 miles. This issue happened at 60'000 miles.(note Haldex is meant to be change every 40’000, so this fits in line with not changing it) But the service book never stated any of this, so much for full-service history. I have sent email to Audi UK stating I'm not happy, but as its a second-hand car not a leg to stand on, but it made me feel better.

so what's next

1. Left foot braking
2. Handbrake 1 click - Could be ABS unit if this does not work - test again to be sure
3. Check earth strap - Never knew about this until reading all the above fingers crossed
4. Does ABS work with Fuse out – Yes ,loads of wet leaves about this time of year.


Could be
Corroded ABS wiring
Earth Strap – this interests me the most and I really hope it’s this.
Haldex Unit
PRE Charge pump
Speed Sensors

It does not sound like Rear Diff – Do you agree?

I will know more at the weekend. But what I find interesting and what is new to me is the speed sensors, as after the tyres where changed the car never felt right, it went back and they stated a weight had come off. But the steering wheel was sitting off centre, they stated it’s because my aftermarket wheels were not Audi. I now think they may have damaged the speed sensors when changing the tyres, if I can prove this even though it’s been months since they were changed I will be looking for compensation.
 
Oh I know mine is an 8P, but it seems this problem is common with Haldex Gen 1 and 2.
 
Sorry mate, but you've just explained a different issue to what the majority are talking about here.

the giveaways are, in your case:
"The noise is there when driving in a straight line, turning, just moving it happens."
AND removing the haldex fuse and you still have the issue.

also haldex oil with grey bits ? Do you mean bits, metal (check if magnetic)? or just some of the oil looked grey ?
 
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audi upgrades
nope I wasn't clear.

I have been driving without the fuse in as with it in I get the problem.

with the fuse in the noise is there. I can drive it but it sounds like the rear wheels are fighting. It is worse when I turn a corner.

Grey as in Metal, I was told but will test.
 
Hmmm but now I think about it, I need to test if the noise is there in a stright line and it comes on when I turn a corner....more testing then.
 
So tested the left foot braking does not make any changes. What I did notice was that pulling away if fine, until there is a need for the four wheel drive (i.e front wheels start slipping) or going round a corner fast. However I had to pull away hard to make this happen, then I had the noise. Then pulling on the handbrake overrides the four wheel drive system and the car drives fine. Therefore my next test is to find the ECU and check if there is power and signal leaving that, to the rear of the car (Haldex etc) . If it is then I can isolate the issue to the back 100% and continue root cause
 
Good diags there, keep us posted.

I had the car in earlier at the garage and it was there overnight so they noticed it this morning, they had it on VCDS, checked the Haldex and all seemed to be fine with that, he seems to think it could be rear diff related, my mechanic has sent some info off to Audi techies and is waiting to hear back from them, so im waiting for that info and will update accordingly.
 
audi techs will say change the lot..i remember reading elsewhere someone spent 2k plus on this problem at dealer........
 
I can imagine they will say that, however the person I use knows better than to go for just that option....lets see what happens.
 
Mine was dragging/binding during tight parking manoeuvres since I bought it nearly 2 years back. I changed the controller, assuming it was that and also as an excuse to get a blue controller but it was still the same. At the weekend I done a Haldex service (new fluid and filter) and also changed the rear diff fluid and it no longer groans or binds up during parking. I'd thoroughly recommend doing it, especially if you don't know when it was last done.
 
Sam, thats good to hear, I did do a oil and filter change recently, but still the same, no change with it on mine, I also removed the fuse last week (31) and the issue still exists, so its not an electrical issue as others are having.
 
Nilz said:
Sam, thats good to hear, I did do a oil and filter change recently, but still the same, no change with it on mine, I also removed the fuse last week (31) and the issue still exists, so its not an electrical issue as others are having.
Click to expand...

If by removing the fuse(31) you STILL have the issue then yours does sound different to most reports like 'woodysjw' has mentioned above. As Sam mentioned above did you change both oils (haldex & diff ) recently ? try removing the abs fuse above the battery and see if that makes a difference - just in case it's the abs/ecu controller. Although superkarl may have a point !
 
The fluid that came out of my rear diff looked old, and smelt bad (not the normal cat **** smell). I'd hazard a guess it was original since it's meant to be a "lifetime fluid" according to Audi (who'd like you to get a new diff, from them, presumably). The Haldex fluid on the other hand, had been changed in the last 20,000 km I'm sure. I'd topped it up at least when I fitted the performance controller.
 
S3LOUD said:
I can relate to that mate. Spent £1500 this month alone on just repairs. Yeah hopefully an oil and filter change should just cure that. If not then whatever you do do not take it to audi for a diagnosis which is what i stupidly did. Got charge £78 and they couldn't tell me anything of any use what so ever -_-.
Click to expand...

I can relate to Audi's silly prices! took mine in for a 1 hour diagnostics check as it was running rough. They then asked me to authorise another 4 hours for more check which I did (and said not a penny more to be spent) they then pulled bits off the engine to come up with a timing chain problem and a £3800 fix. When I said stuff that they said I had to pay another 3 hours to put it back together again. Car ended up being recovered by an audi specialist who still has it now. Audi Bolton did me for over £400 for nothing apart from a car with a box of parts in the boot.
I now have an audi with timing issues, haldex issues and traction control issues....oh what joy! Car will be ace when fixed but probably up for sale!!!
 
Hi i am having the same problem with rear wheels locking up, the problem disappears with the fuse removed. I have changed the oil and controller and the problem persists. When i check measured value blocks it tells me the pump is in "hi" mode all the time even on idle. Is it possible the pump is stuck in high mode? Has anyone else had or heard of this problem?
 
yeah im thinking the pump is faulty and on constantly, just wondering if anyone has come accross this before?
 
eznow said:
Hi i am having the same problem with rear wheels locking up, the problem disappears with the fuse removed. I have changed the oil and controller and the problem persists. When i check measured value blocks it tells me the pump is in "hi" mode all the time even on idle. Is it possible the pump is stuck in high mode? Has anyone else had or heard of this problem?
Click to expand...

I can check mine to see - how do you know its always in high mode within VCD (what area/value block)?
 
i cant remember which block it was but its in 22-awd i went into adv measured blocks and selected the haldex clutch/pump block which tells you the status of the pump. mine is in "lo" mode when ignition is on but soon as the engine is started it stays in "hi" mode till the engine is switched off. If someone without this problem could check if theirs does this would help a lot thanks
 
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eznow said:
i cant remember which block it was but its in 22-awd i went into adv measured blocks and selected the haldex clutch/pump block which tells you the status of the pump. mine is in "lo" mode when ignition is on but soon as the engine is started it stays in "hi" mode till the engine is switched off. If someone without this problem could check if theirs does this would help a lot thanks
Click to expand...
how do we know that is actually what it should do ?
 
Im not sure if it should do that or not, thats why im asking if someone without the problem can check if theirs does the same. If it does the same then i know its normal :)
 
is anyone able to check? this problem is driving me crazy!
 
"The oil flows to a clutch piston, compressing the clutch pack and braking the speed difference between the axles. The oil returns to the reservoir via a controllable valve, which adjusts the oil pressure and the force on the clutch package.
In traction/high slip conditions, a high pressure is delivered: in tight curves (i.e. parking), or at high speeds - a much lower pressure is provided.
Haldex Generation I and II based all wheel drive system is reactive. The coupling activates after a wheelspin is detected. However, the reaction is very quick and just 1/4 of a wheel turn is needed to engage all wheel drive. Electronics is capable of lowering the oil pressure only (when parking, ABS working, the handbrake is pulled, etc.), but cannot pre-tension the clutch.
Under normal driving conditions (driving at the constant speed, no silppage), the torque distribution is 90/10 front to rear. When the clutch is locked, torque is evently distributed between the axles (50/50).
"

Prehaps this means that the "Valve" that controls the pressure is not working right? I know some peoples are cured by oil + filter changes.
 
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I know this is a VERY long thread with 187 posts, but take it from me that has been mentioned countless times and for the lucky few that has worked.
 
Anyone any updates on fixing this problem recently??

Does anyone know how hard / easy it is to change the complete rear diff / haldex, also would any haldex coupling / rear diff fit as I have a spare off a MK1 TT I am thinking of fitting but want to be sure it'll fit before taking mine appart!!?!

Thanks
 
Most garages say treat this as a three hour job. I was always under the impression that the rear diff is specific to the year of your car, i.e. if you have a facelift s3 you will need a rear diff off another facelift car. The differences being facelifts had ESP and the earth strap. However, Ben (Benjamin from this forum) told me that you can fit a pre facelift rear diff to post facelift s3.

The TT ones and R32 ones are the same the same as the 8L s3
 
Thanks Erf, so did you sort your issue out?! Been reading through but didn't see you sorted it yet?

How annoying is it!!!!!!

Thanks again for the input!!

Erf said:
Most garages say treat this as a three hour job. I was always under the impression that the rear diff is specific to the year of your car, i.e. if you have a facelift s3 you will need a rear diff off another facelift car. The differences being facelifts had ESP and the earth strap. However, Ben (Benjamin from this forum) told me that you can fit a pre facelift rear diff to post facelift s3.

The TT ones and R32 ones are the same the same as the 8L s3
Click to expand...
 
jimbob442 said:
Thanks Erf, so did you sort your issue out?! Been reading through but didn't see you sorted it yet?

How annoying is it!!!!!!

Thanks again for the input!!
Click to expand...

Nope, not sorted yet. When I took it Ben, he advised it needs a new rear diff. I've already replaced the rear diff once (bought it off someone on here!), so I'm mentally preparing myself for having to shell out more money. Thing is, I've spent so much money on doing my car up, it is such a shame the 4wd is spoiling it :keule:
 
Erf said:
Nope, not sorted yet. When I took it Ben, he advised it needs a new rear diff. I've already replaced the rear diff once (bought it off someone on here!), so I'm mentally preparing myself for having to shell out more money. Thing is, I've spent so much money on doing my car up, it is such a shame the 4wd is spoiling it :keule:
Click to expand...

Yeah its a sh1tter!! These things are like a money pit!! One thing after another! I know VAG lovers wont like me saying this but I've mostly had jap cars before this and never know so many things to go wrong!! Sensors sensors and more f'kin sensors!! My subaru never went wring and was drove how it was designed to be driven!!!!

Sorry lads for the rant but these niggles really **** me and my wallet right off!!!!

Ok rant finished now to look at the haldex problem again!!!! Haha
 
Just an update from me - I'm now sorted! I bought a 2nd replacement diff(!) item number 221187984879 on ebay and it has done the trick. I'm going to also do haldex oil and filter change and probably replace the oil in the rear diff too just to ensure I don't have any further issues. I wanted to get my car sorted before I sell it, but now I have to replace the top mounts and the tie arms are looking a bit iffy so might have to replace them too - don't think I will end up selling the car at this point now cos I'm just throwing money away that I will never see back....
 
So , it could have been the pre-charge pump only. I see the diff you replaced came complete.
So Erf, who did the work for you and how much did they charge ?
 
I guess it could have been the precharge pump (already replaced one pump!), but when I took it for a service at Parsons Performance they (Ben) did advise me it was the diff.

I got the work done by local mechanic who repairs my mums car - he doesn't have a workshop, does it on his driveway which wouldn't have been fun today as it was pis$ng down. Charged me £100 for fitting the diff (2.5 hrs work) which was pretty decent.

As you're also based in Surrey, I would recommend you take your car to Ben to have a look at. He's based in Lewes, but it's worth the trek!
 
Just to add my tuppence worth, I was getting similar syptoms on my 8P but VCDS scan came up with codes which said; In 4WD, Haldex Controller defective and valve which controls clutch plate angles defective and in ABS Implausible signal Haldex controller. So it's all pointing towards the controller, I have removed it, seems to be the original part and it looked fine, no water ingress or anything, replaced, re-scanned but still getting the codes, in fact when cancelled they now pop straight back up without having to drive the car. I disconnected the plugs from the controller to give me 2WD and all the issues disappear (Traction Control light comes on-dash) but clicking on the handbrake one click on makes no difference and I haven't pulled fuse 31 but as far as I have got is I plan to get a replacement controller and see if that fixes it. I was quoted £771 (Trade) from TPS for a new one, so trying to avoid that but I am going to change the diff oil as well (Haldex and mechanical) and do the Haldex filter. Car has FASH and it was done recently but going to do it again as it looks like the filter wasn't done last time and hoping that will do the trick, will keep you posted in case anything's relavant to anyone else.
 
Erf said:
I guess it could have been the precharge pump (already replaced one pump!), but when I took it for a service at Parsons Performance they (Ben) did advise me it was the diff.

I got the work done by local mechanic who repairs my mums car - he doesn't have a workshop, does it on his driveway which wouldn't have been fun today as it was pis$ng down. Charged me £100 for fitting the diff (2.5 hrs work) which was pretty decent.

As you're also based in Surrey, I would recommend you take your car to Ben to have a look at. He's based in Lewes, but it's worth the trek!
Click to expand...
Well that really is great news to hear you are in the clear now. I had to read through all your posts to remind myself of your efforts. I see you have previously replaced the diff, but because of some mixup with the purchase the pre-charge pump was not included. So I don't see that you ever did replaced it. I have also mentioned in the past my reluctance on buying second hand units from unknown sources bearing in mind so many S3 are plagued with this problem....But then again what do you do ?
I recently changed 2 airbag control units for a MK5 Fiesta (air bag light on) and convinced the problem lay elsewhere even though the computer was showing this unit as a failure. After many months I saw another one for sale and purchased it and it was finally fixed - the 3 third unit replaced ! Each second hand one cost between £15 to £25 - i think a new one cost over £100 so still saving, but only because it was extremely easy part to replace - so no labour charge.
 
I did replace the pump a few months back - bought it off s3Dave from this forum! In total I replaced, the rear diff, the precharge pump, haldex oil and filter and both front wheel speed senors! Finally replaced the rear diff again and we are in luck! Will let you use your imagination to work out how much I've spent! So happy not to have the ESP light permanently on on my dash!!!!

You're right with second hand parts, it's pot luck. What's more painful for me, because I don't know one of a screwdriver from another, I have to pay for labour costs to replace parts. If your more mechanically minded at least you can swap over the parts yourself and most salvage places have a decent returns policy.
 
I know this is a week old, but the question has only just occurred to me.
So you stated the diff only was replaced for the second time and the problem was cured, but yet the removing the fuse was curing the problem.
electrical issue- mechanical component, I don't get that.

Maybe someone can explain the electrical component of the diff !
 
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