Egonvdv

happened for the 1st time today:

on the highway transmission got stuck in 7 .

as i was driving in C (hybrid mode) the engine was operating in full mixed mode, using both engine & battery at the same time
i guess to let the battery help with acceleration...?

slowed down at a toll booth, and then engine did switch gears to 5, only to remain stuck in that gear

i toggled between full electric & petrol, but didn't help

manual shifting did not work

had to to stop and switch off/on engine, and everything went back to normal

of course will contact dealer, but just like to know if this is a known problem ?

CaliBenzDriver

yes, this is a soft-crash or limp-mode of Transmission module. Hopefully your dealer will step up with a true fix.

"Key cycling" is a very effective workaround when you need it in the field. It reboots both the ECU & Tranny and gets a fresh start with problem gone.

How long had you been driving when that happened? Pls describe that trip from the point when you started.

History :
> You've had issue with "low voltage" and "trunk popping open" right ?
​​​​
> The common culprit here may be REAR-SAM...nothing very straightforward.

Egonvdv

started after 1hr driving.
in total went on for about 30 minutes, until i switched engine off.
first bit was 130km/h in 7th gear, there after 90kms in 5th gear

CaliBenzDriver

Interesting facts, thank you.
I bet the 1hr extended drive helped create the lazy shifting. There should be code stored as history.

I am not sure I totally understand: "in total went on for about 30 minutes" ... meaningcar was running almost normal except your tranny kept in high gear, right? This is not good but not a proper "limp mode" either.

Let see what dealer can figure for you with their sharp experience using XENTRY factory tool.

Too bad you still can't read voltage because after the 1 hour mark it becomes increasingly more interesting to watch as VIP modules start acting up.

Egonvdv

yes for about 30 minutes the car was stuck in 7th gear and then in 5th gear
at the same time the battery gave full support. so it wasn't a matter of "mixed" driving, but rather both engine & battery were full on

Egonvdv

dealer has so many internal problems that i can only get an appointment in 1 month

when i said that i didn't feel very comfortable going on a long journey,
they told me i can always call Mercedes roadside assistance if it happened again (or even call them immediately...).

Didn't even get anyone on the phone from the workshop, it was a secretary who told me this .
So i still don't know if it's a common problem or not and what the risk is, of it happening again.

Called the sales person there after to complain and wating for him to phone me back.

Good times.