Charles H writes in July 2020:
Just wanted to let you know I am dealing with what looks to be the same situation now. In my case, I have a 2018 170 ext 4x4 that has ~6200 miles on it.
Recently encountered this same problem when starting the van after it has been sitting multiple hours, either overnight, or all day (engine is cold). The van will start immediately, as before. However, if I put the van in gear (either D or R) and press the accelerator, the engine RPMs do not change (or drop slightly), and the van either doesn't move, or moves very slowly. There are no indicators or warning lights. Once it warms up, anywhere from 3-5 minutes, it drives normally, and if turned off, will restart and drive without issue. This behavior has only happened when we are above 8000 feet (in the Eastern Sierras).
The air temperature has been between 58-80°F for the times this has occurred. The first time this happened was about a month ago, since then it has been occurring with a greater frequency.
I took it to the dealership in San Diego where we purchased it. They said there were no codes and that if it happened again I should leave the van with them for a week or so.
I'm not sure if this behavior is altitude related; if it is they probably won't ever find the problem in San Diego. They were also suggesting a service A, at a cost of $794, which seems high to me. I'm not sure if there is a software update that needs to be installed or not, but I haven't had any software updates installed yet, so this occurred in a "stock" vehicle. It also hasn't occurred when at sea level and below 40 F. Tom S suggested to start with looking at the EGR, and indicated that sometimes either at altitude or in cold weather the EGR will stick open until the engine warms up, at which time it will begin to work. So, I'm going to be looking into that.
WIND: as of July 2020, I am pretty sure that altitude is a factor, since I experienced the same stall multiple times in May 2020 at an altitude of ~8000 feet and temperatures in the 50° to 60°F range. However, cold temperatures may exacerbate it. I had a transmission part replaced in March 2020, the stall is still there, and the dealer has nothing further to say about—they have given up. God help us getting this damned bug fixed by Mercedes—it may be mechanical, but I suspect a software bug.
Mercedes “Service A” is a major ripoff: it’s an oil change overpriced by 4X. I have my Sprinter oil changed at Jiffy Lube for a grand total of about $160 including a $20 Mercedes oil filter and $90 of super premium oil (far superior to the Mobil 1 garbage oil that Mercedes dealers use). Compare that to the $794 cost above.