# Intermittent AWD Failure - Gen IV (4) Haldex - 01155 - Clutch



## AUDI EH3 (Jul 1, 2009)

Since the winter of 2013/2014 when my Audi Warrenty expired. I've been noticing my all-wheel drive isn't engaging some times (Maybe 1:50) when I'm taking off aggressivly from a stop on icey surfaces. I know it works when I'm already moving, also I have no problem drifting the rear end out. 

I got a VCDS cable this winter, so I've been tracking my faults, and its happened about 10 times this winter. :banghead::banghead::banghead::banghead::banghead::banghead:

99% of the information on the internet is for Gen 1 & 2 haldex units, which appear to fail more than the Gen 4. I can inspect the pump for filings when I change the fuild, but thats the only idea i have. 

I checked the plug and have no corrison, and the gen 4 has no grounding strap to fail. I performed the output tests in VCDS: My clutch is engaging and I can feel load on with the parking brake engaged, and the pump runs (altough doesn't sound 100%). There is some clicking when the controler engages the clutch but I don't know if thats normal or not. 

It's due for a haldex fluid change in 10'000 km's but I noted was orginally failing 10'000km after the last Haldex fluid change. 

I'm not sure what to investiage next?



> Address 22: AWD Labels: Redir Fail!
> Part No SW: 0BR 907 554 A HW: 0BR 907 554 A
> Component: Haldex 4Motion 3016
> Coding: 0000005
> ...


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## npace (Sep 3, 2012)

This actually sounds like an intermittent wiring problem to me. Haldex wiring at the connectors has failed due to its location at / above the diff without any real protection from the elements; sometimes the connections get corroded and fail there. I've seen it twice on other cars, and as a result it's just something I always check when I have the car up on a lift. In any event, it wouldn't hurt (or take long) to check the connection and the wiring (IIRC, it's an 8 pin connection). If not, then the pump or the controller (anything electric) would be my next stop.


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## AUDI EH3 (Jul 1, 2009)

Last night I recheck the connector on the controller, everything looked fine. I also checked the fluid level which was slightly over filled. 

I have access to a another controller to test. 

I'm wondering if I sound be focusing on the pump / filter or the controller.


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## AUDI EH3 (Jul 1, 2009)

I think I may be into something here. Due to a fault in my HVAC control module, my car is defaulting to single wire can bus mode. Well if I disable the HVAC module so it returns to two wire mode, my AWD seems to engage flawlessly. 

Now also the controller I received from a friend I noticed supersedes my part number two Letters, so I may throw it in anyways.


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## npace (Sep 3, 2012)

AUDI EH3 said:


> I think I may be into something here. Due to a fault in my HVAC control module, my car is defaulting to single wire can bus mode. Well if I disable the HVAC module so it returns to two wire mode, my AWD seems to engage flawlessly.
> 
> Now also the controller I received from a friend I noticed supersedes my part number two Letters, so I may throw it in anyways.


Interesting. So, new HVAC control module? I'm curious, what do you mean by this? Is it an actual part that needs replacing, or an issue with software in the can-bus? Or do you mean the actual HVAC controls in the cabin? 

Sorry for all the questions, I'm just legitimately interested to know what's going on with this.


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## louiekaps (Aug 12, 2013)

Brent I would have to double check the network diagrams but I would think the hvac would be on low speed can and awd would be on high speed can since it is used for esp and safety related yada yada. That is unless every module uses high speed can, but that is a waste of money which is why most manufacturers use multiple bus's


Edit: however since we share this goofy single wire hvac fault, I'd be interested to see if disabling my hvac would cause my ABS module to stop being broken lol. However, faulty abs modules on a 2009 vag car seems to be as common as water pump failures on tsi's. What did you do to take the hvac off the network?


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## AUDI EH3 (Jul 1, 2009)

Npace , Louie and I share a fault for a open circuit for the can bus system to the HVAC control module ( temp/ac controls interface below the radio). The fault is either within the unit it self(case of a guy in the UK) or a wire running to the unit. I'm waiting on Ponto to test his module to rule out my wiring. 

To disable the unit, I just unplugged the brown connector on back, which can be accessed easily with the radio removed.

Once unplugged two wire mode is restored.


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## louiekaps (Aug 12, 2013)

Ok sounds good. Didn't know if you could disable it with vagcom or whatnot. Next time we get snow I will try this.


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## AUDI EH3 (Jul 1, 2009)

Two wire mode.
http://youtu.be/3tWF455utok

One Wire Mode. 
http://youtu.be/UTSye-ffGw0


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## npace (Sep 3, 2012)

Well, the good news is you know your haldex is fine. Maybe I'm way off here, but I would assume that if it goes back to normal after unplugging the HVAC module, that the problem in within the module itself, and not the wiring behind it.


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## louiekaps (Aug 12, 2013)

Videos private


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## AUDI EH3 (Jul 1, 2009)

louiekaps said:


> Videos private


Fixed


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## AUDI EH3 (Jul 1, 2009)

louiekaps said:


> Brent I would have to double check the network diagrams but I would think the hvac would be on low speed can and awd would be on high speed can since it is used for esp and safety related yada yada. That is unless every module uses high speed can, but that is a waste of money which is why most manufacturers use multiple bus's
> 
> 
> Edit: however since we share this goofy single wire hvac fault, I'd be interested to see if disabling my hvac would cause my ABS module to stop being broken lol. However, faulty abs modules on a 2009 vag car seems to be as common as water pump failures on tsi's. What did you do to take the hvac off the network?


I've been doing lots of reading on this today. It appears that only the comfort databus system (low speed), can run on single wire mode. The way Drivetrain databus (high speed) is amplified it can only run in regular mode. Furthermore the systems are interfaced though the gateway and are not directly connected. So maybe it's all in my head. I might do more video tonight to determine if there is a difference between the modes with a observed effect on my haldex. 


Document explaing the system:
http://www.volkspage.net/technik/ssp/ssp/SSP_269_d1.pdf


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## AUDI EH3 (Jul 1, 2009)

Last night I swapped my controller (Rev. A) for a golf r controller (Rev. C) and it definitely engages different. The ass end will slide out way easier now. I'll be monitoring to see if my code comes back. 

09' A3 on left, 12' Golf R on right 









https://vimeo.com/119572246


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## AUDI EH3 (Jul 1, 2009)

So I replaced my HVAC controller with one from a 2010 (Rev BH). And my can bus system is functioning one two wire mode again. So the can bus fault is within the HVAC module as I suspected. 

On another note, I pulled another intermittent haldex clutch code the other night, so I'm thinking the controller is not the issue.










Ps: while playing around with my HVAC module I determined you only have to replace approximately 10 led to have a white display like the q3. I'm going to look into it more.


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## npace (Sep 3, 2012)

AUDI EH3 said:


> Last night I swapped my controller (Rev. A) for a golf r controller (Rev. C) and it definitely engages different. The ass end will slide out way easier now. I'll be monitoring to see if my code comes back.


This is unusual to me. I'm not sure the difference in the PN, but my OEM one is the exact same part number as what you posted (rev C). I have the HPA haldex controller in there now, but I'm curious as to the actual differences.


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## AUDI EH3 (Jul 1, 2009)

Small update:


As for my car, after changing the HVAC module and Haldex Controller, I performed a full fluid change and inspection. 

I removed the pump and filter and inspected. My oil was full of clutch fillings. It was like this gray soup. Now because the filter would of been $150 Canadian I opted to cleaning my with carb cleaner and compressed air. There were no large chunks on the pump screen. 

The most interesting part was when I finished assembling and refilling the unit. On the first output test of the pump (vcds) it sounded for the first time the pump pressurized, normally the pump just hums. Every time since it hasn't pressurized. 


Long story short I'm still getting the code Intermittently and can feel the AWD drop out. 

I recently performed a output test on a buddies golf r, and you can hear the pump run then pressurize.

So either my pump is shot, or something internal that is preventing the unit from pressurizing. Funny part is the pressure sensor was removed in the Gen 4 unit, by Haldex










Nspace: Depending on the year the car was manufactured would determined which one controller you would have


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## UsualSuspect (Feb 11, 2016)

*4wd*

Hi did u get to the bottom of this problem?

Thanks


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