Audi A5 DPF Crisis: Regen Failure and Smoke Issues

Having some experience with exhaust system repairs, I faced almost identical symptoms on my 2019 Audi A4 diesel last year. The vehicle emissions problem turned out to be exactly what you suspect, a faulty exhaust back pressure sensor that prevented proper DPF regeneration cycles. The emission control system kept throwing error codes, and I noticed the same symptoms: smoke during acceleration and no automatic regeneration cycles. After checking with my regular workshop, they confirmed the diagnosis using specialized diagnostic equipment to test the exhaust sensor functionality. The repair involved replacing the defective sensor and performing a forced DPF regeneration cycle. Total cost came to 245 Euro including parts and labor. Since the fix, the exhaust system has been working perfectly with normal regeneration cycles. Before suggesting more specific solutions, could you share: Current mileage on your A5, Any other warning lights besides check engine, Regular service history, particularly regarding DPF maintenance, Type of driving you typically do (city/highway split) This information would help determine if your situation matches what I experienced and whether other emission control components might need attention.

Last serviced my A5 at 151755 KM, and I actually had the same thought about checking vehicle diagnostics history from recent maintenance. The car maintenance records show no previous DPF issues until now. My auto repair shop ran tests but couldnt pinpoint if its the sensor or something else in the exhaust system. Thanks for the detailed response and cost breakdown, good to know what the repair might cost if its the same issue. Been doing mostly short trips lately which probably hasnt helped the DPF situation.

Thanks for the additional info about your A5. Based on your driving pattern with mostly short trips, this definitely mirrors my A4 situation. The lack of longer drives prevents the DPF from reaching proper regeneration temperatures, which compounds the pressure sensor issue. After fixing my pressure sensor, I made sure to include weekly highway drives of at least 20 minutes to maintain proper engine performance and DPF health. The vehicle emissions returned to normal once both the sensor was replaced and better driving patterns were established. If your car maintenance records show no previous DPF problems, theres a good chance the pressure sensor is indeed the root cause. When my sensor failed, the exhaust system behavior was nearly identical, smoke, failed regeneration attempts, and inconsistent pressure readings. One key test your workshop can perform is measuring the actual exhaust back pressure against the sensor readings. The diagnostic data should show a clear mismatch if the sensor is faulty. My repair costs were 245 Euro, but prices for parts have increased slightly since then. Would strongly recommend getting this addressed soon, as continued driving with a malfunctioning DPF system can lead to more expensive repairs down the line.

Thanks for that detailed advice on diagnosing the sensor issue. My A5 situation does sound really similar to what you experienced with short trips affecting the DPF. The car maintenance records and symptoms match up closely. Will definitely have the workshop check the actual back pressure readings against the sensor data. Good point about the potential for bigger exhaust system problems if left unfixed. Just scheduled an appointment to have them run those diagnostics tests tomorrow. Knowing the approximate repair costs helps with planning, even with some price increases, its better than risking more expensive damage. Appreciate the tip about regular highway drives too. Will make sure to work those in once the pressure sensor is sorted out.