S3 4WD Problem?

[FazS3]

Hi lads,

Hope all is well...

Need some help, going to look at a friends S3 this week, how ever it seems as though power is only going to the front wheels? There is no knocks or bangs, my feeling is the haldex will need replacing? I will be taking vagcom with me to scan it but just thought if I could potentially get a head start in identifying the issue?

Thanks

Faz

 

[superkarl]

hi, it seems your mate might be in the same boat as me. My 4wd didnt seem to know what it wanted to do, i've had the fuse pulled for a while now trying to find out what could be wrong. When i scan mine i get this:
Address 22: AWD
Controller: 02D 900 554 B
Component: HALDEX LSC ECC 0006
3 Faults Found:
01312 - Powertrain Data Bus
37-00 - Faulty
01316 - ABS Control Module
49-10 - No Communications - Intermittent
01314 - Engine Control Module
49-10 - No Communications - Intermittent

its the powertrain databus fault which is most interesting. i've done plenty of searches and cant find solid answers. i may have to replace my haldex controller, but until then my car is coming off the road and im dropping the haldex coupling out to inspect it.

with the communications errors i assumed it would be electronic at first, maybe faulty wiring. getting under the car though and there is hardly any room. supposedly there is an earth from the haldex module to the diff, but i havnt found it. Some people have cured 4wd faults by checking/cleaning and replacing this. i cleaned all i could see to no prevail.

until i know for sure that its the haldex module, im not gonna fork out silly money for one. i've got an audi contact going to look at it at warrington audi for me some time, hopefully soon. If i find out anything i shall let you know on here. id like to know what else you find. maybe we can get to the bottom of it, because front wheel drive REALLY F**KS ME OFF!

Superkarl

oh and check the fuse first, number 31, your problem could be as simple as that.

 

[sportquattro]

Probably an obvious one but has he checked the fuse?

 

[barters3]

i had the precharge pump go on mine. doesnt throw any codes but stops the haldex working.

Skoda Octavia Haldex Coupling Precharging Pump on eBay (end time 15-Oct-10 13:21:31 BST)

Only one on ebay and is a little pricey, although they are around £350 from audi.

there is always tt complete rear diffs on ebay but nobody seems to want to split.

If it is the problem and you need one; i was chatting to the guy at tsr performance, TSR Performance Store they do a lot of 1.8t conversions into mk2's etc so have a lot of surplus tt running gear.
i dont know how to test the pump in position though.

 

[superkarl]

my precharge pump is going crazy, constantly pumping and buzzing and ticking. when i was on vagcom i could run a test, i did it and it said it was ok, vagcom stopped it, ran it, repeatedly and it did waht it said.

 

[barters3]

i didnt realise you could test the pump. may be worth a shot.

 

[<tuffty/>]

Another (and cheaper) possibility is the earth strap to the rear subframe/diff/where ever it connects too.... there has been a thread on here in the past I seem to remember where haldex issues were down to this strap corroding through... simple replacement sorted it all out..

<tuffty/>

 

[superkarl]

i had a da good look for this the other day and couldnt find it. there was the wires coming through the boot floor, connecting to the haldex module, then another from the module to the pump. would it be an earth from the module onto the subframe/diff?

 

[FazS3]

hmm...Sounds like it could be a number of things causing it! Isit a common fault on these? Any negative side effects in driving it in 2wd mode?

 

[<tuffty/>]

i had a da good look for this the other day and couldnt find it. there was the wires coming through the boot floor, connecting to the haldex module, then another from the module to the pump. would it be an earth from the module onto the subframe/diff?

Its a braided copper strap IIRC... back of the subframe in the middle I seem to recall, not got my car in the air anymore so can't really look on mine but have a trawl through the search for something like 'haldex' and 'earth'...

<tuffty/>

 

[S3 Rav]

Faz I see your car was up for sale on pistonheads the other week. What you got up your sleeve mate??

 

[FazS3]

Faz I see your car was up for sale on pistonheads the other week. What you got up your sleeve mate??

Was only testing the water mate I still have the RS4 and keeping it.

Getting rid of the R32 possibly to make way for the S3.

How you doing mate?

 

[Welly]

Also, adding to the above, I've seen one recently which, on the Haldex plug on the rear diff, had all the pins inside corroded and couldn't make a connection.

Cut the plug off, spliced, soldered and heat shrank the wires up, loomed it up, job done.

Communication with the Haldex ECU again.

 

[superkarl]

hmm...Sounds like it could be a number of things causing it! Isit a common fault on these? Any negative side effects in driving it in 2wd mode?

massive wheels spin and fwd characteristics which is massively crap. let us know what you find. this does seem to affect alot of people yeh, people end up buying full diffs, without knowing what exactly went wrong.

welly i checked a plug and it looked absolutely sound, i was very suprised just how clean it was.

i had a thought today though, the precharge pump which builds the oil pressure up to engage/disengage the clutch is going a bit mad, perhaps it doesnt have enough oil and cant get the pressure required. ebay it is to get haldex oil and filter................

 

[S3 Rav]

Was only testing the water mate I still have the RS4 and keeping it.

Getting rid of the R32 possibly to make way for the S3.

How you doing mate?

I'm good bud apart from some c&£t the other week that decided he wanted my wing mirror for himself!! All good apart from that. All good with you mate, yea the rs4 is beautiful definitely a keeper!