ABS Problems with 2012 Audi Q7

[Lion Heart]

Before I go too far down any rabbit hole... Simple question: is there a simple way to test/tell if you ABS control module has lost its coding?

 

[Dr Sheldon]

It it were a bad bearing, ABS ring etc would that throw up all of the other ABS faults we are seeing here as well as the obvious linked wheel speed sensor fault?

Who knows - Who Cares - Possibly - Maybe - We may be solving problems we do not have !!

It will at least clear one fault and then we can progress from there,

 

[Dr Sheldon]

Cold be faulty wiring or magnetic ring - time for the mark 1 eyeball examination of the ring.

I recall a Suburu Imprezza many moons ago. The Ring looked great - It was new !! Had a complete new driveshaft fitted !!

However the driveshaft was wrong as it had 2 teeth less than it should have had !! I'm lucky in that I had heard of a similar fault on a forum somewhere and I looked at frequency with a scope and nailed it.

Otherwise that for sure would have messed with my mental health !!

 

[Lion Heart]

It will at least clear one fault and then we can progress from there,

Yes, my thoughts exactly. Which is why I'm interested to know if you can tell/test if the ABS control module has lost its coding.

 

[Dr Sheldon]

Unfortunately accessing the ABS ring is not easy AT ALL on these. I believe (?) you must remove the wheel bearing to access the ABS ring, and these are pressed in rather than bolted on, which requires a special tool to remove and refit

No Pain No Gain my Friend !!

These Premium Vehicles do come with faults, of course, at a premium !!

I work on all sorts all day every day !!


If you look at @Uwe 's footer he is spot on !! I have no axe to grind, I get paid for my time, knowledge and first time fix success rate. However and this is my personal experience All the German cars VAG, BMW, Mercedes ... are over engineered, over complicated, unforgiving and only any good when not broken !!

The exception being OPEL - Absolutely among the best cars in the world before the French got hold of them !!

Thanks to the Germans, I'm a Bosch Trained and Qualified Master Tech - Which has won me awards and accolades - Love it !! However I'm sure I was not this arrogant and obnoxious before I embarked on that journey with Bosch !!

I would poop my pants at the thought of buying a German Vehicle and I can fix them !!

 

[Lion Heart]

So , you would recommend I buy the $400 tool and remove the wheel bearing to check the ABS ring before finding out if the ABS control module has lost its coding (which is what I suspect could be the issue)?

No problem buying the tool if it's likely to fix the issue, but I'm not convinced it will be the ABS ring over the ABS Control Module?

 

[Dr Sheldon]

Yes, my thoughts exactly. Which is why I'm interested to know if you can tell/test if the ABS control module has lost its coding.

It would throw a DTC and ALL 4 Wheels would be Equal driving in a straight line - END OF !!

There is no such thing as a 3 Wheeled Q7 - There Will be No Coding String for such a Vehicle !!

 

[Lion Heart]

So the ABS control module on the Q7's has no coding??

 

[Dr Sheldon]

So , you would recommend I buy the $400 tool and remove the wheel bearing to check the ABS ring before finding out if the ABS control module has lost its coding (which is what I suspect could be the issue)?

Nope Just READ !!!

In Post #10 I wrote

In an ideal world you want to scope both front sensors to know why they report different speeds I would like to see them graphed on VCDS - Just the front two with the scale set correctly ?

I would also like a VCDS capture with the Fault Code Present for Freeze Frame

I write these sentences to help - I get no pleasure from shortening the life of my keyboard

 

[Dr Sheldon]

So the ABS control module on the Q7's has no coding??

Are you ok ??

 

[Lion Heart]

I would also like a VCDS capture with the Fault Code Present for Freeze Frame

How do I do this BTW?? Which section?

 

[Lion Heart]

Yes, all good thank you. The question was easy: So the ABS control module on the Q7's has no coding??

"There Will be No Coding String for such a Vehicle !!"

 

[Dr Sheldon]

Yes, all good thank you. The question was easy: So the ABS control module on the Q7's has no coding??

"There Will be No Coding String for such a Vehicle !!"

Let get some context !!

There is no such thing as a 3 Wheeled Q7 - There Will be No Coding String for such a Vehicle !!

 

[Dr Sheldon]

Still you choose to IGNORE -

Post #10

Have you absorbed #23

 

[Dr Sheldon]

Yes, all good thank you. The question was easy: So the ABS control module on the Q7's has no coding??

"There Will be No Coding String for such a Vehicle !!"

I've come across motorists similar to self many times - We recommend you travel on that "bus" not just any bus !!

 

[Dr Sheldon]

Any openings for a MT in Canada - What dollar they paying ?

4 days 12 hours a day ??

 

[Dr Sheldon]

The question was easy: So the ABS control module on the Q7's has no coding??

Have another attempt at Patronising / being condescending at my expense -I dare You !!

 

[Uwe]

is there a simple way to test/tell if you ABS control module has lost its coding?

Yes, it would have a fault for "Incorrectly Coded" or something like that.

-Uwe-

 

[Lion Heart]

Thank you, Uwe. That's precisely what I needed to understand.

At least I can now eliminate that from the probable causes.

 

[Lion Heart]

So quick update on this as I could use some advice...

Bottom-line is I need to get this car fixed to sell it. I've lost a lot of money on this car already, and hoping to minimize the loss so want to spend as little as I can to get it fix and sold.

I'm going to test the wiring between the Front Left wheel speed sensor and the ABS control module (I'm hoping this wiring is direct from the sensor to the control unit). I'll find out which wire it is and test for resistance to check it's not the wire.

So, that will be done, so that will be off the table as possible cause. But I think it won't be that.

Remembering that I've replaced the wheel speed sensor and the steering angle sensor already, I have a feeling it's either the ABS Ring or the ABS Control Module. Can you think of anything else that's a likely cause looking at my scans?

So, which to do first:

OPTION 1: ABS Ring. I will need to buy a tool for this. I don't think an $80 puller will have the power to shift it (it's likely rusty too). It's inside the hub and needs to be pressed in/out (no bolts). I saw hydraulic tool online for thousands of dollars. Not an option. I did find a tool a while back on Amazon that said it could do it, circa $400:

https://www.amazon.com/OEMTOOLS-37342-Bearing-Remover-Installer/dp/B08XW7FXVN/ref=pd_ci_mcx_pspc_dp_d_2_t_1?pd_rd_w=OkkfU&content-id=amzn1.sym.568f3b6b-5aad-4bfd-98ee-d827f03151e4&pf_rd_p=568f3b6b-5aad-4bfd-98ee-d827f03151e4&pf_rd_r=HHJQWF0KS81J9V6PS456&pd_rd_wg=do1Ss&pd_rd_r=9da8eb2d-2f9d-4457-b462-a93cc3018f1d&pd_rd_i=B08XW7FXVN

Reluctant to spend $400 on a use-once tool unless I really have to. I may be able to get the bearing out using a press by removing the entire hub. I have a feeling that this job is going to be an absolute bitch without that hydraulic tool

OPTION 2: ABS Control Module. I can buy a used one on eBay for around $250. It will need to be coded using VCDS after installation (I have the full version of VCDS). I found a page on Ross Tech for the coding on this car and it says to contact Ross Tech to get the coding. I think this job would be a lot easier than the wheel bearing?

OPTION 3: Another likely possible cause - any ideas?

Interested to know what route you'd take on this, and all help very welcome!