S3 AWD problem

[old-git]

Hi. My son has a problem with his S3. Although the prop is rotating, the rear wheels are not being driven so it is a FWD car at the moment. Checked the fuses. Could the problem still be electrical or are we looking at serious money?

 

[obi_waynne]

I reckon it is a mechanical issue with the diff. What year is it? Audi had a few different diff setups. Are there any error codes from Vagcom?

 

[pgarner]

the A/S3 isnt really quattro, it uses the haldex clutch to engage the rear wheels. as waynne said check you the haldex controller section on diagnostics see if theres error codes.
there should also be a section on there to test the controller. is there an issue with the ABS traction control ? the front wheels have to slip 1/4 turn i thin before it engages the clutch.
will try and do digging on this for you see what i can find out

 

[pgarner]

ok quick search turned up this

you may find a fault code 65535
taken from ross techs wiki page

65535
Contents [hide]
1 Internal Control Module Memory Error
1.1 Internal Control Module Memory Error
1.1.1 Possible Causes
1.1.2 Possible Solutions
1.1.3 Special Notes
Internal Control Module Memory Error

Internal Control Module Memory Error
Possible Causes
Control Module housing leaky > Control Module wet
Wiring from/to Control Module faulty
Control Module faulty
Possible Solutions
Check/Clean Wiring from/to Control Module
Replace Control Module
Special Notes
This fault is NOT to be ignored when found in a major and/or critical system (Airbag, ABS etc.).
When stored in other unimportant systems (Radio etc.) the general suggestion is to ignore it unless you notice functional limitations. Within the warranty period dealers are usually required to replace such control modules, but there have been a couple of cases with similar codes where these are getting ignored due to flaws in the control module software. If in doubt please refer to technical bulletins and similar documents provided by the vehicle manufacturer.

seems to have been a big problem with alot of cars esp on the skoda side - haldex ECU was revised at a later date
wont tell you the price of the haldex controller unless your sitting down

there was a few that had found one of the plugs for the haldex controller had came out - sorry no mention of where it is other than near the rear diff

 

[woodmeister]

Yeah it's almost definatle the haldex controller, i've done a few of these in the past couple of years, more so on earlier model tt's but essentially the same setup, with the same problems.

try local scrap yards for a rear axle complete with diff, sometimes they throw in the controller for next to nothing without realising their value. It will need to go onto vag.com before and after.

 

[old-git]

Thanks, guys.

Update - disconnected the controller plug and it was full of oil.

I have been advised by my local garage that the car shouldnt be driven as there is a chance that the diff could lock up sending car into a spin. Any opinions on this?

Car is a T reg.

 

[pgarner]

traction control and ABS might not work correctly. when traction is lost on the front wheels the haldex activates to kick in the rear

have you tried cleaning the plug out and seeing if it works again ?

 

[LemonS3]

Don't have traction control n the abs works fine.

Had it checked with a vag-com today n it came up with rear diff clutch fault, obviously worn out. Found someone on ebay selling the rear end off a 2004 R32, does anyone know if this will fit a 1999 audi s3?

 

[pgarner]

what ages ? will check ETKA

 

[pgarner]

02d 525 646b - housing for 2003 s3- marked as quattro models
02d 525 646b - housing for 2003 golf - shows all 2.8 and 3.2 engines

 

[LemonS3]

Thanks pgarner, I was pretty certain it will fit but I just wanted confirmation.

 

[pgarner]

thought i had been lucky and found a clutch for it, but it turned out to be a flange
if you need help with part numbers give me a shout

 

[LemonS3]

Cheers pgarner!

It's all sorted now, I have 4wd again
Got a complete rear end off ebay (diff, haldex, subframe, drive shafts, hubs, wishbones, arms) which came off a golf r32 that had only done 14,000 miles. Took me about two days to do due to a few problems and because it kept blooming raining, just got to bleed the brakes which is turning out to be a pain in the arse!

 

[herb]

good news about the 4wd!!!
i presume you have the same brake setup as me? and when i changed a brake line a few months back it was a pain. so i can empathize!!

 

[pgarner]

please say you didnt let the reservoir run dry otherwise you will need VCDS (used to be vag-com) or audi to bleed the ABS pump.

also worth remembering that vag like to do things the hard way so looking at the layout it would look like
reservoir is on the LHS of the engine bay (front offside) this mould mean normally the rear nearside would be the furthest away not in that chassis !
the lines run from the master cylinder across the bay and down the opposite side of the car meaning the the rear offside is the furthest away by fluid path.

way to bleed them properly is :
rear offside
rear nearside
front nearside
front offside
bottom master cylinder screw
top master cylinder screw
then abs pump bleed using vag tool #### - or vcds.
iirc this 17 step procedure that pumps roughly 1 ltr through each calliper.



got to admit the vag brakes arnt the best i changed mine just over a fortnight ago and started hearing a new knocking sound around a week ago.
pulled the wheel off on friday and found that one of the retaining clips had sprung off causing the line to hit against the wheel. now need to order a new set of brakelines again as its rubbed through the pvc and started on the braiding so want it replaced rather than the chance of it bursting

 

[LemonS3]

I'm pretty sure I didn't let it run dry as hardly anything came out the lines even after leaving it over night. I read somewhere that there might be a proportioning valve or something. Think I'm going to just bleed it all again and go from there, I've got brakes it's just there's a lot of pedal travel.

 

[herb]

I'm pretty sure I didn't let it run dry as hardly anything came out the lines even after leaving it over night. I read somewhere that there might be a proportioning valve or something. Think I'm going to just bleed it all again and go from there, I've got brakes it's just there's a lot of pedal travel.

my brake pedal felt solid then started the car and it went spongy 2 or 3 times. bleed the system each time with the same result then had to take it for its mot retest but it passed the brake test:blink: but after a week the pedal went back to feeling solid