Audi Q3 Brake Issues: Spongy Pedal and Vibrations

Had a similar issue with my 2015 Q3 2.0T last summer. Have some experience maintaining older cars and doing basic repairs, but brake system issues are best left to professionals. The symptoms you describe match what I experienced, spongy brake pedal and vibrations. Initially thought it was just worn brake rotors, but the diagnosis revealed an undervoltage issue affecting the brake system electronics. This was causing irregular pressure in the hydraulic brakes and making the brake calipers engage unevenly. Took it to a workshop where they: 1. Ran a full diagnostic scan 2. Checked the battery and charging system 3. Tested the brake fluid for contamination 4. Inspected the entire brake system Total repair cost was 240 Euro which included: New battery installation, Brake fluid flush, System recalibration, Full brake system inspection To better assist with your specific case, could you share: Current mileage on your Q3? When was your last brake fluid change? Have you noticed any electrical issues, like dim lights or slow starter? Any warning lights on the dashboard? The brake system problems could be similar to what I faced, but these details would help confirm if its the same underlying issue.

Thanks for the feedback. My current mileage is 62708 KM and last service was done in March, which included oil change and general inspection. The squeaky brakes only started about 2 weeks ago. Following your suggestion, I checked and there are no warning lights on the dashboard. The starter and electrical systems seem to work fine, with no issues with lights or other electronics. Your experience with the brake calipers is interesting, the symptoms do sound similar. The brake pads were replaced during last year's service, so I was surprised to encounter these brake system issues so soon. The pulsating through the metal brakes definitely makes me concerned about potential uneven wear. Will get it checked by a professional soon, but wanted to verify if others had similar experiences first. The 240 Euro cost reference is helpful for budgeting.

Those are concerning symptoms, especially since you had the brake pads replaced recently. On my Q3, the pulsating turned out to be partly due to uneven pressure in the hydraulic brakes, but there was also some warping on the brake rotors which contributed to the vibration. Given your mileage and recent brake pad replacement, I would suspect either: 1. Brake rotors developing hot spots from uneven wear 2. A partial failure in the brake hydraulics causing irregular pressure 3. Contaminated brake fluid affecting the system pressure The squeaky brakes combined with pulsation often indicates metal-on-metal contact somewhere in the system. Since youre not getting any warning lights, its likely a mechanical rather than electronic issue. The fact that your brake pads are relatively new makes me think the rotors might be the culprit. On my Q3, even after fixing the electrical issue, I ended up needing new rotors about 2 months later due to the damage from the uneven brake pressure. Would strongly recommend getting it checked soon before the issue potentially causes more extensive damage to the brake system. My total repair ended up being higher than initially quoted because I waited too long, the rotor replacement added another 180 Euro to the bill.

Thanks for the detailed info. Good to hear your diagnosis was straightforward and the repair costs were reasonable. With my mileage at 62708 KM and recent brake pad replacement, I was worried about a major system failure. The disc brakes do seem to be behaving similarly to your case. No electrical problems on my end though, so maybe the root cause is different. The squeaking from the metal brakes started only 2 weeks ago, and the brake system problems are definitely getting more noticeable. The hydraulic brakes acting up despite new pads is concerning. If the brake rotors are warped as you mentioned, that would explain the pulsating. Better to get it checked now before any serious damage occurs. Your experience with the delayed rotor repair adding 180 Euro to the bill is a good warning. Will schedule a professional inspection this week. The workshop can do a proper diagnosis of the brake shoes, rotors, and hydraulic system. Rather pay 240 Euro now than risk bigger repairs later. Thanks again for sharing your experience, really helped understand what might be going on.