NHTSA Complaint #11633414 — 2023 MERCEDES-BENZ SPRINTER 3500

Vehicle suddenly lost ability to accelerate. After driving narrow mountain roads with a lot of downshifting and upshifting, vehicle was on a long, gradual downgrade, then approached a long, slight (4%?) upgrade. Vehicle would not maintain speed and began to decelerate. Pushing the accelerator to the floor did nothing. Attempted to manually shift gears, but transmission would not downshift, or upshift. This almost resulted in being rear-ended by a semi. The speed limit was 55 and vehicle had decelerated to ~25 mph by the time I found a place to pull over. I stopped and was able to shift into Park. Revved engine and it behaved normally. I shut off engine for 1 minute and then restarted. Transmission and all other systems worked fine and continued to work normally for several hundred miles since then. There was no CEL, or other warning. There was no indication that it entered "Limp Mode." I suspected that something went wrong with the logic in the electronic transmission. Mercedes Benz dealership could NOT find any codes logged in the OBDC. The service manager told me, "It might have been some kind of computer glitch." This was a 2-lane, country road. The semi was behind me, and several cars were behind the semi. For about a mile there was no place to pull over. One impatient driver passed both the semi and my Sprinter in a "no passing" zone. We were all fortunate that there was no collision.