The 2019 Mercedes-W205 C200 AMG High-Efficient Vehicle has gearbox issues.

[Matt865]

Hello there,

I have been experiencing issues with the automatic gearbox in my C class, which has logged 38,500 kilometres. Unless you utilise the paddles on the steering wheel, the automatic transmission will not change up from sixth gear to seventh gear and beyond.
As expected, the gearbox shifts down, and up and down movement of the paddle shifters produces the desired effect.

After driving on the self-learning cycle, the issue of not being able to shift into seventh speed at around 40mph reappears, even after resetting the automatic gearbox.
I was informed by a Mercedes specialist that this model does not require a fluid replacement until 75,000 miles, however the automatic gearbox has not been serviced or changed since it was new.
I had similar issue last year, but it went away in the late summer after a particularly warm spell. Now it's back.
A scanner from the local garage, an Autel Maxisys 908s, detected four suspicious wheel speed signals—one for each wheel.
Based on my little exploration of the web, I have discovered multiple instances of W205 auto gearboxes failing to engage in 2019 models.

Does anybody have any ideas as to whether the issue is with the sensors or the software, and how much it will probably cost to fix it?
Would appreciate any suggestions for an independent MB specialist (within a reasonable distance from Northwich, Cheshire) with an appropriate Star system who can diagnose the problem and fix it the first time around; I'm thinking of taking my car in for diagnostics.

Even when the engine temperature is normal, the electric cooling fan continues to run after shutting off the engine, which is another intermittent defect. This seems to begin occurring after driving through numerous puddles.
It seems to be a winter issue; I experienced the same thing last year, but it went away in the summer. Maybe Mercedees are starting to hate our rainy season.

Though my two issues pale in comparison to the ones that Mr. Starmer is presently facing, I would really appreciate any feedback you could provide.

[CyberNinja]

Has Mercedes installed any new software on the vehicle?

[Matt865]

I have had the car since November 2022, so no.

[AMG33D]

Do you really think it won't alter at speeds of 75 mph or more?
It was aggravating, but not a defect, that my own MB 7G auto wouldn't shift up until I was travelling at least 70 mph.

[Matt865]

Your responses are greatly appreciated.
I will investigate, but I haven't seen any differences at 75 mph. Going from sixth to seventh gear at forty miles per hour in comfort mode is par for the course.
Have learned that the vehicle has received three upgrades over airwaves, which are as follows:


November 26th, 2018: Communication module optimisation
Enhanced Mercedes-Me module 9.11.23
Update for the Mercedes-Me module 3.6.21

Missing from all previous updates

[CyberNinja]

The gearbox won't shift to seventh gear until you reach 75 mph or above, according to an update that was applied to some vehicles for "emissions" reasons. Typically, the dealer will take care of this while the vehicle is in their care, and the owner is never informed.