carricrf

I just had an experience that I wanted to share where all the sudden I had these 3 error message show up every time I started the car, and before I did anything but start the car. I had it in to the stealership and they said it was bearings and the speed sensor at $2,475 to replace on the right side (interesting??)... They said the stethoscope heard bearing noises so I took the bait and $1,695 less in the bank account. They needed to order the speed sensor (can you believe that! because these parts are on many Audi models!)... In any case they said by the way your tires have different wear, so you might want to have that checked out too. Long story short, 2 months earlier, I ran over a Torx bit in a 1/2" socket wrench that must have fallen into the road. The T10 long torx when completely through the tire, so of course I replaced it.... Little did I know this was the cause of all my problems. The odd tread wear on the tires was now completely screwed up by adding 1 new tire (I had intended to change the other 3, but did not get right around to it.. wish I did now!)... What I found out was when I changed the other 3 tires, all the error messages went away. What the situation was is that the tires now different sizes would now create differences in the rotation speeds (you can watch via the VCDS monitoring) and once that happens, it impacts ABS, TPMS, Steering, Wheel Position, and EPB. Even the Audi Dealer did not see that and if I proceeded with the Speed Sensor replacement only, I would have wasted yet another couple hundred dollars. Our cars are very sophisticated on these measures so what might work for other cars as far as cutting corners, it won't for these. I had not realized my tire wear was as bad as it was and had I realized that I would have changed all 4 at the same time and saved myself a lot of money and frustration. I just wanted to share my experience with others. Things are not always as they appear on the surface and look at everything holistically and not just troubleshoot starting with only the error codes. Happy Motoring.

mikesvwservice

Sorry it cost you so much money because of the tires...

My Wife's 2015 Q7 now has the ESC, ABS and TPMS lights on the dash now. After scanning and clearing the DTCs, they come right back.

Scan said electrical issues with the speed sensors and a mechanical issue with the left, rear speed sensor, so went ahead and ordered all four speed sensor from Rock Auto (with ship, tax and 5% discount come out to $102.22).

Hope this takes care of my "issue(s)"...

Thanks for sharing your story!
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UPDATE: After putting the new wheel speed sensors on, the dash warning lights were still on.

After getting up to 3-5 mph, the ESC and ABS lights went off (the TPMS stayed on).

I scanned the Q7, printed, deleted the DTCs and then drove it. Everything worked and ALL the warning lights stayed off.

So, in my case, my wheel speed sensor(s) replacement solved my problem.

Valpo A7

If I remember correctly you can have 3/32nd of an inch tread depth difference and still be in tolerance for the computer.

mikesvwservice

Yes, I read that too...

I forgot how these Quattros' are "sensitive" to "mixed tires", tread depth, and tire air pressure...

I'll post the results after I put the wheel speed sensors on.