Audi A6 Brake Pedal Vibration Points to Warped Rotors

I experienced a similar issue with my 2013 A4 diesel last year and want to share my experience, as someone with moderate DIY car maintenance experience. The symptoms you describe with your brake pedal closely match what I encountered, that pulsating through the brake pedal during highway braking is quite distinctive. While initially I also suspected warped disc brakes, it turned out the root cause in my case was an undervoltage issue affecting the brake control module. The workshop diagnosed the problem by connecting their diagnostic equipment. The undervoltage was causing irregular signals to the hydraulic brakes system, creating that pulsating sensation. The fix involved replacing some electrical components and recalibrating the brake module, costing 240 Euro in total. However, your issue could still be mechanical, problems with brake pads or rotors can create similar symptoms. To better assist, could you provide: Any warning lights on the dashboard? Does the pulsation happen at all speeds or only highway speeds? Any unusual sounds when braking, like squeaky brakes? Have you noticed any changes in brake pedal travel distance? Getting these details would help determine if your issue is electrical like mine was or if it's mechanical. Since this involves your braking system, I recommend having it checked soon rather than waiting for it to potentially worsen.

Thanks for the feedback. Regarding my brake issue: after 191387 KM, I just had the car inspected by a certified mechanic. The diagnosis showed unevenly worn disc brakes and warped rotors causing the vibration. They recommended replacing both front brake calipers along with the rotors. They also noticed the brake fluid was slightly low and needed topping up. The quote came in at 850 Euro for parts and labor. Given the high mileage and the critical nature of the braking system, I scheduled the repair for next week. They mentioned its quite common for brake components to need replacement at this mileage interval on these models.

Thanks for the update on your A6 brake situation. My A4 hit similar issues around that mileage point. The metal brakes definitely show their age after 190000km, and uneven wear on the rotors is a common problem. The 850 Euro quote actually sounds reasonable for the complete job including both front brake calipers and rotors. When I had my brake shoes replaced last year, the mechanic pointed out early signs of uneven rotor wear, but I waited too long and ended up with warped rotors that required complete replacement. The low brake fluid level you mentioned could indicate normal brake pad wear, but its good they caught it during inspection. Regular fluid checks are crucial for maintaining proper hydraulic brakes performance. Getting this fixed next week is a smart move. These symptoms tend to worsen quickly once they start, and compromised braking at highway speeds isnt worth the risk. Let us know how the car feels after the repair, you should notice a significant improvement in brake pedal feedback and overall braking performance.

Thanks for the thorough responses! Just wanted to update after getting the brake repairs done. The mechanic was spot on, replacing the brake rotors and calipers completely solved the pulsating issue. The hydraulic brakes now feel solid and responsive, with no vibration even during hard braking at high speeds. The brake system repair took about 4 hours total. They showed me the old parts, the rotors had visible scoring and uneven wear patterns that explained the vibration. They also did a full brake fluid flush while everything was apart, which wasnt in the original quote but only added 60 Euro to the total. Actually glad I didnt wait longer, as the mechanic pointed out the old brake calipers were starting to stick slightly. The new disc brakes perform noticeably better, with much smoother and more consistent braking. For anyone hitting similar mileage on these cars, its worth getting the brake components inspected before problems develop. The final cost came to 910 Euro with the added fluid flush, which seems fair given the amount of work and new parts installed. The braking performance feels like new again, so Im satisfied with the investment in safety.