VW Passat TDI DPF Issues: Black Smoke and Power Loss

I had a very similar issue with my VW Golf TDI from 2003. As someone who does basic maintenance but leaves major repairs to professionals, I recognized these classic DPF issues right away. The symptoms you describe match exactly what I experienced, engine warning light, power loss, and exhaust problems. In my case, the diagnostic revealed a faulty exhaust back pressure sensor, which was causing incorrect readings and preventing proper DPF regeneration cycles. The repair cost me 245€, which included replacing the pressure sensor and performing a forced DPF regeneration to clear accumulated particles. After the fix, the diesel exhaust problems completely disappeared and power was restored. Before proceeding with specific advice, could you share: Current mileage on your Passat, Driving patterns (mainly city or highway), When was the last DPF regeneration done, Any previous particulate filter maintenance history This information would help determine if your issue is similar to what I encountered or if there might be other underlying problems with your DPF system. Also, there can be a connection between driving patterns and DPF issues, short trips often prevent complete regeneration cycles, leading to more frequent problems with the particulate filter system.

Last service was done 2 months ago at 61103km. The mechanic found no issues back then. The reduced power issues you mentioned match my experience perfectly. After reading about the pressure sensor connection to DPF problems, that could explain the symptoms. The particulate filter warning showed up just days after my dashboard lit up with warnings. The exhaust system definitely needs checking based on your description. 245€ sounds reasonable compared to a full DPF replacement, which I was worried about. I mostly do highway driving, so clogging shouldnt be the main issue. Did your emission control system show any other error codes besides the DPF pressure readings?

Thanks for the additional details about your vehicle history. The emission control system in my Golf only showed the low pressure DPF code, similar to your case. Since you mentioned mostly highway driving, this further supports my suspicion of a faulty sensor rather than a clogged filter. The reduced power mode is a protective measure the engine computer activates when detecting DPF pressure issues. In my repair, after replacing the faulty sensor, the system needed a complete diagnostic reset to clear the reduced power state. Highway driving typically helps maintain proper DPF function, which makes the sudden appearance of problems more indicative of a sensor or control system fault rather than particle buildup. The timing, just after a clean service inspection, also points toward a component failure rather than maintenance issues. Before my repair, I also noticed the power loss got progressively worse, especially during acceleration. If youre experiencing the same pattern, its very likely the same pressure sensor problem. At 61000km, your DPF system should still be functioning properly with mainly highway use. Would recommend having the exhaust back pressure sensor checked first before considering more extensive repairs to the diesel engine or DPF system.

Thank you for that detailed sensor explanation. Your Golf situation does seem very similar to what I am experiencing. The progressive power loss during acceleration matches exactly what my Passat is doing. Based on your feedback and my highway driving patterns, I feel more confident now that its likely the pressure sensor causing these DPF issues. The particulate filter itself should still be in good condition given my driving habits and relatively low mileage. I will have the workshop check the exhaust back pressure sensor first. Starting with the most likely and cost-effective fix makes sense rather than jumping straight to major diesel engine repairs. Will also ask them to do a full diagnostic reset after fixing the sensor, as you mentioned this was needed to clear the reduced power state. Your repair experience has been really helpful in understanding these symptoms. Will book the car in next week and update once I know if it was indeed the same pressure sensor problem you encountered with your DPF system.