Transmission Issue (electronic?)
04-30-2019, 01:11 AM
#1
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C250 W205
Transmission Issue (electronic?)
The car has started jerking when changing gear, but only in certain circumstances.
If the car is decelerating (e.g. freeway doing 100km/h, slow down to around 80km/h due to a slower car in front), when you go to speed up to overtake you get a jolt through the car as it changes gear; ranges from a subtle jolt you feel through the seat to a big lurch that actually moves you in your seat.
The car often bogs down as well momentarily (loses power).
The most severe examples I have experienced have been when I have the Distronic engaged; with the Distronic on I've experienced 2 - 4 BIG lurches as the car starts to try to accelerate back up from around 80km/h and it momentarily loses power.
In these more severe cases, the auto start-stop light (the A with the arrow around it) on the dash will go out. For the remainder of the trip, the car will then also jolt between 2nd and 1st gear when coming to a stop at traffic lights (not badly, but noticeable). It will also then rev harder than usual when idling at lights, and you can feel the engine vibrating your seat.
If you park the car and go back to it after it has been off, everything goes back to normal.
It is not doing this stuff every trip, but happens at least a couple of times a week.
We have it booked in to be checked over this week, but curious if this sounds familiar to anyone?
On a side note, the auto start-stop function basically never works. I drive the car in C mode with the auto start-stop turned on, but the A light on the dash is almost always orange/yellow so the engine never actually shuts off at traffic lights. It used to turn green after you had been driving for a while and the car would shut off at traffic lights, but more recently it never turns green. Don't know if it may be related?
Any feedback appreciated!
If the car is decelerating (e.g. freeway doing 100km/h, slow down to around 80km/h due to a slower car in front), when you go to speed up to overtake you get a jolt through the car as it changes gear; ranges from a subtle jolt you feel through the seat to a big lurch that actually moves you in your seat.
The car often bogs down as well momentarily (loses power).
The most severe examples I have experienced have been when I have the Distronic engaged; with the Distronic on I've experienced 2 - 4 BIG lurches as the car starts to try to accelerate back up from around 80km/h and it momentarily loses power.
In these more severe cases, the auto start-stop light (the A with the arrow around it) on the dash will go out. For the remainder of the trip, the car will then also jolt between 2nd and 1st gear when coming to a stop at traffic lights (not badly, but noticeable). It will also then rev harder than usual when idling at lights, and you can feel the engine vibrating your seat.
If you park the car and go back to it after it has been off, everything goes back to normal.
It is not doing this stuff every trip, but happens at least a couple of times a week.
We have it booked in to be checked over this week, but curious if this sounds familiar to anyone?
On a side note, the auto start-stop function basically never works. I drive the car in C mode with the auto start-stop turned on, but the A light on the dash is almost always orange/yellow so the engine never actually shuts off at traffic lights. It used to turn green after you had been driving for a while and the car would shut off at traffic lights, but more recently it never turns green. Don't know if it may be related?
Any feedback appreciated!
05-02-2019, 11:18 AM
#3
Senior Member
I have multiple transmission shifting issues but the dealer either can't reproduce or tells me it's all normal. I have a very hard jerk when shifting from 3-4 at 20mph, and they said they "reprogrammed and fixed it" but now it also jerks from 4-5 at 40mph. So basically they made it worse. Honestly, the simple fact is that the 2015-2016 7G transmissions are not that great, or the software isn't up to snuff and they haven't bothered to fix it. The 9G is light years better from my personal experience.
As for the auto-start feature. I had a similar issue and it turned out my battery required replacement. The auto-start either will not engage, or the icon will turn orange (IIRC), if the battery capacity is not optimal to maintain the car shut off. Either way, i'd have MB confirm.
As for the auto-start feature. I had a similar issue and it turned out my battery required replacement. The auto-start either will not engage, or the icon will turn orange (IIRC), if the battery capacity is not optimal to maintain the car shut off. Either way, i'd have MB confirm.
05-02-2019, 06:38 PM
#4
MBWorld Fanatic!
I "think" there might be a cmapaign to update your tranny software - as a "campaign" that is free - call your dealer with your VIN# and they can pull that up and check
