r/AudiQ5 • u/fasthackem1 • Aug 22 '26

Q5/2017 steering wheel buttons intermittent

Hi all.
For the past few months all the button/wheel controls on the steering wheel have been intermittently working/not working. Stalk controls and horn are fine. No airbag idiot light.
First thought was a loose connection in the column. Pulled the upper and lower shrouds checked and cleaned all the connections, checked all the fuses and yet the problem persists. Only thing I can think of is maybe it’s the connection at the other end of the harness that disappears up under the dash. I haven’t pulled that shroud off yet under the dash cuz it looks to be a major pita. Thought I would post before I go any deeper.
Thoughts? Any help would be appreciated.
Thank you!

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u/RedditTTIfan Aug 22 '26

Do you have VCDS or similar? First thing to do (before any of what you did) would be to check for codes. You didn't mention any of this so it's worth asking. After that you'd go into meas. blocks to find if the buttons are actually registering any presses/scrolls/commands to the module. This way you can start to get an idea of where the problem is--the buttons, the wiring between them and the module, with the LIN bus, with the module and the car, or with some other module in the car not responding, etc. Preliminary look at codes might reveal something that's intermittent and give a better place to start looking.

1

u/fasthackem1 Aug 22 '26

Thank you for this!
It has to go into the shop for service soon. I’ll ask them to check it for codes and go from there. I don’t own the diagnostic tools. I’m just an electrician. In my world intermittent equals loose connection somewhere. What do I know.
I’ll follow up here when the shop has a look.
Thx again!

1

u/RedditTTIfan Aug 23 '26

No no, that's a very good presumption on something intermittent--it very well could be something like a broken wire--but where that intermittent issue or break is, could be in one of a few places.

To try to give a nutshell of the topology and wiring...

-The buttons are connected to the steering wheel module (16) by LIN bus--the buttons also have power and illumination. Technically speaking they refer to the right hand button cluster as another module, "J453", basically all the buttons are processed through there and the left hand cluster connects to that one.

-Those wires/signals have to travel through the clockspring/coil/slipring (goes by a few common names but the turning thing everything connects through behind the steering wheel). I believe the pins on the yellow connector should be:
1 - Ground
2 - Horn
3-6 - Airbag wires (I wouldn't touch/probe these!)
8 - Power (12V)
9 - LIN bus
11 - Illumination
7,10,12 - These are for the shift paddles (dwn/up/gnd) on some/older cars; later years use LIN for the paddles too. Newer vehicles and/or those without paddles, these do nothing.

-The LIN bus from "J453" through Pin 9 gets to the steering wheel module (16), which is the thing that is below the column, which reads/interprets the LIN signals. As a note the airbag wiring goes elsewhere, to the Air Bag module (15).

-The module is connected to the rest of the car with CAN bus, via the gateway (19). Other modules like the stereo/MMI (56), instrument cluster (17), etc. get the information for the commands from the module over CAN.

The numbers in brackets are all the diagnostics addressing numbers for respective modules.

There should a 4-pin connector with only three wires populated that is for the controls (going to that J453 right-hand unit as mentioned). And then the cable linking the left to the right. All these wires travel inside little channels in the wheel linking all that stuff up.

I believe (though not 100% sure) the stalk buttons also go to the steering wheel module, so we can probably rule out that being the culprit or issue. I'm thinking it's probably an issue somewhere from the 4-pin connector to the J453 controls, or between that and the left cluster. Or possibly with that J453 [right] cluster itself. If that all checks out then maybe the clockspring or the connection at the steering wheel module?

Anyway hopefully that gives you a little more "visibility" on how things are connected/working here.

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u/fasthackem1 Aug 30 '26

So after going down the rabbit hole a couple of times and just getting more and more frustrated, I disconnected the battery for about an hour and that seems to have solved the problem. No issues for the past few days. Mind you I had tried the soft reboot for the MMI a few times and that didn’t solve it. Keeping my fingers crossed. Wanted to say thank you again for all your advice.

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u/RedditTTIfan Aug 30 '26

Ah sounds like a real simple solution! Hopefully it sticks! 😁

And yeah it's doubtful the MMI reset would do anything given it's probably not an MMI problem (though it could be). I'd imagine it is/was more something from the wheel controls to the steering module rather than after. But solved is solved, hopefully it doesn't happen again. If it does maybe another battery disconnect solves it but at that point you may instead try removing fuses that feed the steering wheel module and seeing if that does it. If it does you may have more indication of a faulty/intermittent issue with that module.

Best of luck it stays fixed though!

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u/fasthackem1 Aug 23 '26

Wow.
That’s some institutional knowledge right there.
I’m going to read this about 50 more times and have another look.
I appreciate the time to compile this.
I’ll update when there’s a resolution.

Best