B200D jumps idle

[Viktoenagy19]

Hello everyone,

I want to share my experience with my Mercedes W246 B200D 2017 automatic car, which I am still not happy with. I purchased the car in October 2022, and it had 22,000 miles on it. I bought it from Tradecentre UK Birmingham, and since then, I have had multiple issues with it.

During my first visit, I had to get a new battery because it had a slow crank. Then, during my second visit, I had problems with the gearbox, and they had to replace the Air MAF, clutch and flywheel, service the gearbox, and clutch pressure valve.
However, I have noticed that when I turn on the car with a cold engine, ( doesn't matter is 0 or +12 outside) it feels like it jumps, and I can feel kicks or jumps. I am not sure if it's the engine or gearbox causing this. It usually happens for the first 5-10 minutes during idling, and kicks 2-3x a minute Sometimes, it doesn't happen for a few minutes, and then it kicks a few times again. But, if I go for a few miles drive and idle it again, everything seems fine.

I am not sure what this is or what's causing it. If anyone else has a B200D automatic transmission, could you please let me know how your car idles?

Also I feel like my gearbox has a growling sound and vibration, which is more intense than what I would expect from this car. Maybe it's just a bad design, but I am not sure.

Lastly, I have a diagnostics software that shows a permanent fault code, but Mercedes and an independent expert said there were no faults at all.

Please let me know if you have any input on this matter. I would greatly appreciate it.

Kind regards,
Viktor

 

[DSM10000]

The new battery should have sorted the fault code. Was it cleared?

 

[Viktoenagy19]

The new battery should have sorted the fault code. Was it cleared?

Tradecentre did the battery change in October,
I just got the diagnostic device to check it myself. But No faults found by mercedes dealer also another independent garage run diagnostics and also comes back clear.
Only I can see this with my laptop....
stop and go, takes a good few Miles to drive to kick in otherwise won't work.
First time to have mercedes... All other cars before these basic things worked instantly.

 

[Dickie Fix]

When my W246 was new, the gear changes were a bit harsh, but a software update sorted that out. I've not had the engine kick or jump on tick-over, but when I start the engine from cold and the outside temperature is freezing, the gearbox fluid is a bit thick and putting it into D makes the car jump a bit and the first few gear changes are not as smooth as when the fluid has warmed up.

I've read that the 7-DCT gearbox is very sensitive to the fluid level and I wonder if when they serviced it, they didn't follow the correct procedure to check that the fluid level was correct. Apparently, + or - 50ml either way can make all the difference. You need a calibrated dip stick and a means of accurately measuring the gearbox fluid temperature using Xentry or similar.

 

[Viktoenagy19]

When my W246 was new, the gear changes were a bit harsh, but a software update sorted that out. I've not had the engine kick or jump on tick-over, but when I start the engine from cold and the outside temperature is freezing, the gearbox fluid is a bit thick and putting it into D makes the car jump a bit and the first few gear changes are not as smooth as when the fluid has warmed up.

I've read that the 7-DCT gearbox is very sensitive to the fluid level and I wonder if when they serviced it, they didn't follow the correct procedure to check that the fluid level was correct. Apparently, + or - 50ml either way can make all the difference. You need a calibrated dip stick and a means of accurately measuring the gearbox fluid temperature using Xentry or similar.

Interesting, possible permanent damage was done to car gears due to oil and clutch issues, just was cheaper to fix this way to replace clutch + flywheel instead changing the complete gearbox. Reading other forums and people had to rebuild the complete gearbox when they had same or similar issue like I had.