VW Jetta TDI: DPF Issues Causing Power Loss & Smoke

I dealt with similar symptoms on my 2003 VW Golf TDI. Had moderate experience working on diesel engines, but this particular issue required professional diagnosis. The low pressure reading from a faulty exhaust back pressure sensor was causing similar problems, engine light, reduced power, and excessive smoke. The emission control system was getting incorrect readings, which prevented proper DPF regeneration cycles from starting. Took it to a workshop specializing in diesel particulate filter issues. They diagnosed the defective sensor and replaced it for 245€ including labor. This resolved the problems completely, no more warning lights, proper power restored, and normal exhaust behavior. Before jumping to conclusions though, would need to know: Current mileage on your Jetta? When was the last DPF regeneration performed? Any recent maintenance or repairs to the exhaust system? Are you doing mostly city driving or highway miles? These details would help determine if your symptoms match what I experienced or point to a different DPF-related problem. Different driving patterns can significantly impact how the particulate filter performs and when issues develop.

Just had my latest service done 2 months ago at 130674km. Thanks for the detailed response, those symptoms match exactly what I am experiencing. Seems the exhaust pressure sensor theory makes sense given how similar our issues are. My mechanic never mentioned the DPF pressure sensor specifically during past maintenance, so that could definitely be the culprit causing the diesel engine power loss. Will have them check the exhaust system thoroughly, especially the pressure readings, before attempting a forced DPF regeneration. The 245€ repair cost you mentioned sounds much more reasonable than I feared.

Having gone through this exact repair on my Golf TDI, can confirm that getting the pressure sensor checked first was the right call. When my workshop initially tested the exhaust back pressure readings, they were way off normal parameters, which explained why the diesel particulate filter wasnt performing proper regeneration cycles. After sensor replacement, worth noting that it took about 2-3 full DPF regeneration cycles before the system fully normalized. Initial smoke cleared up completely once the particulate filter started working efficiently again. The total repair time was under 3 hours. Just one tip from my experience, make sure they also inspect the electrical connections around the sensor area. My mechanic found some minor corrosion on the wiring that could have eventually caused similar symptoms. Cleaning those connections was included in the original quoted price and helped prevent future issues with the exhaust pressure monitoring system. Keep us posted on what your mechanic finds. Given your mileage and symptoms, sounds like you caught this early enough to avoid any permanent damage to the DPF system.

Appreciate the detailed insights, especially about checking those electrical connections. The Jetta actually goes in for service tomorrow morning. After reading about your experience, I feel much more confident about the potential diagnosis and repair path. Really helpful to know about the multiple regeneration cycles needed after the sensor replacement. That will prevent unnecessary worry if the emission control system takes a few days to fully stabilize. The reduced power and exhaust issues started affecting my daily commute, so getting this resolved quickly is important. The similar repair cost is a big relief too, was worried this might turn into a major DPF replacement. Will definitely have them thoroughly check both the pressure sensor and wiring condition. Will update the thread once I get the final diagnosis and repair results from the workshop.