S3 8L Haldex Controllers

[Eoin]

Hi,

Does anyone have a definitive guide to the Haldex Controllers for the S3 8L? I note from the parts guide that S3's used Audi part numbers 02D900554B and 02D900554C and in addition there is a 02D900554D listed for the later Audi TT's/Golf's. Some use the O ring gaskets, some the metal gasket and the one I originally had on my S3 (02D900554B) with no gasket. My question is: are all controllers exactly the same functionality wise? Do they all work with the facelift model (>2001) which has the ESP switch? Can you identify the controller via visual inspection, gasket type etc? As I need to replace my controller I want to make sure I get the right one. Thanks.

 

[Eoin]

No reply needed as I got the problem sorted. The controller I got from an Audi TT is now working perfectly.

 

[s3mad_dude]

Has this finally cured your skipping wheel whilst turning on full lock?

 

[Eoin]

yep, everything is ok now. The original Haldex Controller was gone and I replaced it but the connector on the replacement was damaged resulting in a partially connected controller which gave me AWD all the time + binding + no response from controller on VAGCOM. A cable tie sorted it out and now it's working as it should.

 

[s3mad_dude]

Oh cool. I get the odd skip sometimes. Not always but sometimes. Can you share with me a few pointers about where the haldex controller is located and what to look for within the connection? Can I just clean the plug connectors?

 

[Eoin]

The Haldex controller is located to the side of the casing containing the haldex clutch - between the propshaft and the rear diff. The connection that gave me trouble is located behind the rear diff...just in front of the rear exhausts box. There is a plate attached to the car near the diff which is held in by 2 8mm bolts. The connection between the haldex controller and the car's wiring loom is attached to this plate. If you remove the 2 8mm bolts you can remove the plate and then separate the connector from the plate and then open the connection. Sometimes this connection is corroded and needs to be cleaned or replaced. In my case the clip was broken and the connector wasn't joined properly giving me the problems. I'd suggest you run a VAGCOM scan on the Haldex Controller module and the ABS module and see what that gives you. It might point you in the right direction. Either way it's not that big a job to check the connector, you might get lucky and find the problem there. There is another connector you can check which goes from the haldex controller to the precharge pump (located near the controller). This is sometimes corroded or filler with oil. It's more difficult to reach and a ramp is useful here. If all the connectors are ok you could be looking at a wiring problem further up in the loom, a faulty haldex controller or precharge pump or even the ABS module.

Hope this helps...good luck!

Eoin

 

[s3mad_dude]

Wow - thanks very much for the advice! That's certainly a great post to help me get started. I was just going to buy a new controller but Audi wanted £980. So, I'll try the connections first and go on from there. Thanks very much.

 

[thegoal007]

there are always some out there for second hand sale, but huge caution advised when purchasing from an unknown source because this is a 'very' common problem! not sure of anyone who went down the buy new route unless they didn't have to fork out for it i.e under warranty.
This is one of the VERY MUST DO's when test driving a second S3 - a few full locks turns.
I was fortunate to source a brand new one (old shelf product) from the USA and cost me around £155 all delivered...I think i was very lucky.
Take your time, keep looking and just make sure you buy once to try and get it right otherwise you might then start thinking the issues are elsewhere (red herring)...maybe! And in the mean time just drive accordingly knowing it happens - I did for a number of years.

PS. This is provided this is where the issue is. No doubt you hear stories at the end of the scale where they simply change the haldex oil and filter and it's cured.

 

[s3mad_dude]

Top tips thanks. Mine doesn't always do it. Sometimes it's fine for days/weeks and then it does when I'm parking. Haldex has been changed on time since day 1. I've never missed a service (a very much loved baby). Because it's intermittent it sounds like a dodgy connection so I'll start there. If it doesn't work I'll try a new controller. I'm not going to buy a second hand one that may/may not work. I can't be ***** with the hassle.

 

[MrMCT]

Hi

I'm in need of a controller too. Comms error and intermittent AWD.

Can I ask where you got yours from? See if they have another I could order.

Thanks!

 

[Eoin]

I got mine from a breaker, Brendan Conlan Automobiles in Rathangan which is about 40 miles from Dublin....he doesn't have too much stock so I doubt if he has other ones lying around...mine was from a 2001 Audi TT and worked perfectly. Cost was €150 which was a good deal. New they are very expensive, I was quoted €1865 from Audi Dublin so second was the only way to go for me. You see them on eBay sometimes also. Before you buy it's worth doing a VAGCOM scan if you haven't already done so....check earth strap, connections etc. Good luck!