Mercedes Sprinter Diesel Warning Light and Power Loss

Sounds familiar. I had similar symptoms in my Sprinter: warning light, reduced power, and a bit of a smoky exhaust. For me, it turned out to be a faulty exhaust back pressure sensor. The sensor basically tells the engine control unit (ECU) how much pressure is in the exhaust system, which is important for the DPF (diesel particulate filter) to function properly. When it fails, the ECU gets incorrect readings, which can lead to reduced power and other problems. Have you checked the pressure sensor? It's usually located near the DPF.

Thanks, that's helpful! Where exactly is the pressure sensor located? And is it something I could potentially replace myself, or is it better left to a professional? I'm not a total newbie, but I don't want to mess anything up.

Okay, so on my Sprinter, the exhaust back pressure sensor was pretty accessible, right next to the DPF itself. You should be able to see it if you follow the exhaust system from the engine back. Replacing it yourself is possible if you're comfortable with basic tools – usually just a wrench or socket set. However, keep in mind that DPF issues can be complex, and if the new sensor doesn't fix the problem, there might be something else going on with the exhaust system or the DPF itself. If you're unsure, it might be best to take it to a workshop. They can properly diagnose the issue and make sure everything is working correctly. In my case, they hooked it up to a diagnostic computer to confirm it was the pressure sensor before replacing it.

Thanks a lot for the advice! I took it to a local workshop, and you were spot on – it was indeed the exhaust back pressure sensor! They replaced it, and the total repair cost was 245€. The reduced power is gone, no more smoke, and the warning light is off. Appreciate the help!