I've recently taken ownership of my first mercedes after years of owning BMW's. I've got a 2011 ML350 CDI 4Matic BlueTec (non ad-blue version). A couple of occasions this past week coming to the end of my commute to work (about 12 miles) when I stop at the traffic lights, the revs are sitting around 900 and a very minor vibration/shudder coming through from the engine. Normally revs sit around 700-750. If i put in N, the revs drop to back to normal, 700-750, vibration/shudder goes away. Then when I put it in D to pull away, the revs go back to 900 and it drives fine. The first time this happened, after stopping and starting the engine, put it in drive, the revs went back to normal. The 2nd occasion this happened, same set of lights, coming to the end of my commute, 900 rpm, into N, down to 700-750. When i got to my work, i went between N & D a few times, everytime I went to D, 900 rpm, N - 700-750.
Is the above signs the car trying to do a DPF regen, or is it something else going on? The other thing to add is I filled the car for the first time a couple of days before this started and I added to the tank some Wynns Xtreme Diesel System Clean, one of the things this supposedly does is maintains cleaniness of the EGR Valve and DPF - so actually, is what I'm seeing a result of adding this fuel additive in as it was fine before? I have also read about the throttle position sensor being a common issue, but if it was this, surely the revs wouldn't drop when putting it in N without touching the accelerator pedal? The final thing is I do have an Autel code reader, I did plug it in both occasions and no error codes were showing. Any advice appreciated as the vehicle is still in warranty. Thanks in advance
Is the above signs the car trying to do a DPF regen, or is it something else going on? The other thing to add is I filled the car for the first time a couple of days before this started and I added to the tank some Wynns Xtreme Diesel System Clean, one of the things this supposedly does is maintains cleaniness of the EGR Valve and DPF - so actually, is what I'm seeing a result of adding this fuel additive in as it was fine before? I have also read about the throttle position sensor being a common issue, but if it was this, surely the revs wouldn't drop when putting it in N without touching the accelerator pedal? The final thing is I do have an Autel code reader, I did plug it in both occasions and no error codes were showing. Any advice appreciated as the vehicle is still in warranty. Thanks in advance
