A3 TDI DPF Woes: Dark Smoke and Failed Regeneration

Last month my A4 2.0 TDI (2017) showed similar symptoms. The exhaust system diagnostic revealed a faulty back pressure sensor, which was causing incorrect readings for the DPF system. The vehicle diagnostics confirmed that the sensor was sending erratic signals, leading to failed regeneration cycles and excessive smoke. These pressure sensor issues can become serious if left unattended, as they affect both DPF function and overall vehicle emissions. The malfunctioning sensor tricks the engine management system into thinking the DPF is either too full or too empty, causing incomplete regeneration cycles. The repair required: Complete diagnostic scan, Removal and replacement of exhaust back pressure sensor, System reset and validation, Test drive to confirm proper DPF regeneration The symptoms disappeared completely after fixing the sensor. Based on your description, the diagnosis sounds accurate. The job requires specific diagnostic equipment and expertise with modern diesel emission systems. Worth noting that using a non-genuine sensor can lead to repeated failures, so OEM parts are recommended for this repair.

Thanks for the detailed response about your DPF sensor experience. Just had my A3 fixed for the same emission control issues last week. The symptoms match exactly what you described, failed regeneration and dark smoke. Can you remember the total repair cost for your A4? My auto repair bill was steep at 780 Euro for parts and labor. Also curious if youve had any recurring issues since the pressure sensor replacement? My mechanic warned that other exhaust components might need checking in a few months due to the prolonged sensor malfunction. Noticed mine runs much smoother now, but still keeping an eye on the car maintenance indicators just in case.

After getting my A4 fixed by a certified diesel specialist, the total repair cost came to 245 Euro, which included the OEM exhaust back pressure sensor and labor. This was significantly less than the initial quotes I received elsewhere. The engine performance has been flawless since the repair, with no recurring issues over the past eight months. The vehicle diagnostics confirmed that the sensor replacement resolved all problems, no more failed regenerations or dark smoke during acceleration. The exhaust system is working exactly as intended now. My mechanic did a thorough check of related components and found no additional wear from the faulty sensor. Your 780 Euro bill seems quite high compared to the typical cost for this specific repair. While prices can vary, replacing the back pressure sensor alone shouldnt reach that amount. It might be worth getting an itemized breakdown of the work performed, as they may have replaced additional components. Since the repair, my DPF regeneration cycles have been completing normally, and fuel consumption has actually improved slightly. Regular monitoring shows all emission-related parameters are now within normal ranges.

Thanks for the insights and support from everyone. Finally got my A3 sorted out at a different shop. After reading your experiences, I decided to get a second opinion from a diesel specialist recommended by a. They ran a complete vehicle diagnostics test and confirmed it was indeed the back pressure sensor causing the DPF issues. Total repair came to 320 Euro including parts and labor, way less than the original quote. The exhaust system is working perfectly now, no more black smoke or failed regenerations. The new mechanic took time explaining everything, showed me the faulty sensor, and even gave tips for preventing future emission control problems. The engine runs smoother than before, and fuel consumption has improved noticeably. Really glad I checked here first, saved me nearly 500 Euro and found a reliable mechanic in the process. Been three weeks since the repair, and the car performs great with no warning lights or issues.