Escalade Diesel Spews Dark Smoke After DPF Failure

I had nearly identical symptoms with my 2020 Cadillac XT6 diesel engine. The reduced power mode activated suddenly during highway driving, accompanied by dark smoke and strong exhaust fumes. Initially, the DPF pressure readings suggested a blocked filter, but further diagnosis revealed a faulty exhaust back pressure sensor. The actual repair required replacing the defective pressure sensor and performing a complete DPF regeneration cycle. This was quite serious since a malfunctioning pressure sensor can lead to incorrect DPF regeneration timing, potentially causing permanent damage to the particulate filter. The symptoms you describe, especially the combination of reduced power, dark smoke, and intense exhaust smell, strongly point to a sensor issue rather than just low pressure in the DPF. With these diesel engine problems, getting an accurate diagnosis is crucial since misdiagnosing sensor issues as DPF problems can lead to unnecessary filter replacements. Consider getting a second opinion from a dealership or specialized diesel workshop, as they have specific diagnostic equipment for pressure sensor testing. These symptoms should not be ignored, as continued driving could lead to more extensive DPF issues.

Thanks for sharing that experience, it really helps with my situation. Your problem does sound identical to what I am experiencing with my Escalade. I am actually leaning towards getting that second opinion now, especially since the pressure sensor seems to be a common failure point in these diesel engine systems. Just wondering, do you remember roughly how much you ended up paying for the repair? Also, has your exhaust system been running smoothly since the fix, or have you noticed any other issues with the particulate filter?

You were right to consider a second opinion. In my case, the repair was completed last month, and the emission control system has been working flawlessly since then. The exhaust pressure sensor replacement cost me 245€, which included diagnostic time and labor. This was actually less expensive than I initially feared. The diesel engine performance returned to normal immediately after the repair. No more reduced power mode, dark smoke, or strong exhaust smell. The particulate filter is now operating correctly since the new pressure sensor provides accurate readings for proper regeneration cycles. The diagnostic reports confirmed that the exhaust back pressure sensor was indeed defective, causing false readings that triggered the warning lights and power reduction. A proper diagnosis saved me from an unnecessary and much more expensive DPF replacement. If your symptoms match what I experienced, definitely have a specialist check the pressure sensor before considering more extensive repairs to the emission control system.

Following up on my case, I took the car to another mechanic who specializes in diesel engines. Turns out my first mechanic was indeed off with the diagnosis. Just like in your case, they found a faulty exhaust pressure sensor causing incorrect readings in the emission control system. The total repair came to 290€ including parts, labor and diagnostic time. The mechanic also performed a DPF regeneration cycle after installing the new sensor. The reduced power issues cleared up immediately and the dark smoke disappeared completely. The intense exhaust smell that was bothering me is now gone. I am glad I got that second opinion instead of jumping straight into more extensive particulate filter repairs. The diesel engine now runs perfectly and all warning lights have stayed off. Makes me wish I had asked around on this forum earlier before visiting the first mechanic.