A6 Diesel Rough Running Due to Injector Quantity Drift

Had a similar issue on my 2013 Audi A4 2.0 TDI. The fuel injection system showed drift compensation errors through onboard diagnostics, causing rough idle and performance issues. The root cause was a faulty injector in cylinder 2. These diesel injectors require precise calibration, and when they fail, they disrupt the entire fuel injection balance. The drift compensation tries to adjust, but eventually cant compensate enough, triggering the check engine light. The repair required: Full diagnostic scan, Injector removal and testing, Replacement of the defective injector, Reset procedure for the injection control module, New copper sealing washers This was a serious repair that needed immediate attention. Continuing to drive with a failed injector risks damaging the engine and can affect other components in the fuel system. The repair took two full days due to the complexity of accessing and calibrating modern diesel injectors. Make sure to find a shop with proper diagnostic equipment for diesel fuel injection systems. Unusual parts replacement without proper testing often leads to unnecessary costs and repeat issues.

Thanks for sharing your experience. Your injector issue sounds exactly like what Im facing with my A6. Before booking the repair, could you share what the total cost was for fixing it? Also wondering if you had any other fuel economy issues pop up since the repair? Just want to make sure the compensation adjustment fixes the problem long term, as these fuel injection repairs can get expensive.

After getting it fixed last month, I can confirm the reset quantity drift compensation issue was fully resolved. The mechanic replaced the defective injection valve which completely solved the rough running. Total cost was 515 Euro for parts and labor, which included the specialized onboard diagnostics testing. Since the repair, fuel economy has actually improved by about 10% compared to when the injector was failing. The car sensors are all showing normal readings now and performance tuning parameters are back to factory specs. Having proper injection timing makes a huge difference. These modern diesel fuel systems are sensitive, but once properly repaired, they tend to stay reliable. Three months later, no warning lights or fuel-related issues have returned. Getting it fixed by a shop with the right diagnostic equipment was definitely worth it, even though the repair cost was significant.

Thanks for the input. After reading about your experiences, I finally got my A6 sorted. Took it to a different shop that specializes in diesel injection systems. Their advanced onboard diagnostics confirmed it was indeed an injector issue, just like many of you suggested. The repair cost came to 490 Euro, which included the new injector, system reset, and full testing. The mechanic showed me how the airflow sensors were also affected by the faulty injector, but no additional parts were needed once the injection system was fixed. The car runs perfectly now, no more rough idle or check engine lights. Fuel economy is back to normal too. Much better experience than my first mechanic visit where they just kept resetting the system without fixing the root cause.