Audi Q4 E-tron ABS Warning & Weak Brakes Alert

I had a very similar issue with my 2019 Q3 e-tron last year. The brake pedal felt spongy and the ABS warning light was constantly on, seriously affecting brake performance. After using basic diagnostic tools at home without success, I took it to a workshop. The mechanic found that the brake system was bled incorrectly during routine maintenance, which affected the pressure sensor readings and triggered the warning lights. The repair process took about 2 hours, they properly bled the brake system and recalibrated the pressure sensor. Total cost was 90 Euro. Your symptoms sound familiar, but to better assist could you share: Current mileage on your Q4? When was your last brake service? Does the brake pedal feel soft or does it require more force than usual? Are there any other warning lights besides the ABS? Vehicle safety should be the top priority here. Until you get it checked, try to limit driving and maintain extra distance from other vehicles since your brake performance might be compromised.

Thanks for the helpful reply. My Q4 has 159346 KM and had its last service 3 months ago. The brake pedal definitely feels harder than usual and requires more force. The Electronic Stability Control light also comes on occasionally with the ABS warning. The diagnostic tools at the workshop showed multiple fault codes related to the brake system. They specifically mentioned the pressure sensor might need replacement due to irregular readings. I am concerned about parts availability since these electronic components can sometimes be on backorder. Has anyone had experience with replacement parts lead times for the Q4 brake system components?

Thanks for the additional details. Based on those symptoms and fault codes, this definitely sounds more serious than the bleeding issue I had with my Q4. The combination of a hard brake pedal, ABS warning, and ESC light points strongly towards a failing brake booster pressure sensor, exactly what the workshop suggested. When my brake system had similar issues after 150000 KM, I ended up needing the complete sensor replaced. The hydraulic brakes were functioning, but the electronic assistance was compromised, explaining the increased pedal force you are experiencing. Regarding parts availability, my sensor replacement took about 4 days to arrive. The actual repair took around 3 hours since they needed to recalibrate the entire brake system after installation. Total cost was around 450 Euro including parts and labor. The hard brake pedal and warning lights indicate reduced brake performance, so I agree with getting this fixed quickly. The faulty sensor readings can cause the brake system to default to a reduced assistance mode as a safety measure. Given your mileage and the fault codes, replacing the sensor is likely the right solution rather than just recalibration. The good news is that once replaced, the brake performance should return to normal immediately.

Thanks all for the input. After getting the Q4 checked at another workshop today, they confirmed it needs a new brake booster pressure sensor. Parts should arrive within 3-4 days and total repair cost estimate is 480 Euro including labor. The technician explained that the hard brake pedal feel is due to the brake system defaulting to reduced power assistance mode when it detects irregular pressure sensor readings. While basic brake performance is maintained for safety, the electronic brake assist features are limited. Given the similarity to other cases shared here and the matching symptoms, I feel confident this is the right diagnosis. Will schedule the repair for next week once the parts arrive. Really appreciate all the insights about repair times and costs, helped set the right expectations when discussing with the workshop. Definitely learned that any changes in brake performance or warning lights need immediate attention to maintain proper vehicle safety. Will update once the repair is complete.