W206 2023 C43 AMG - Reporting on the the resolution of the extremely jerky shifting in the lower gears: Had an appointment with the dealer but I decided to try resetting the trans control unit (TCU), and then drive normally for a while for it to 're-program' itself. After having done so and driving for a couple of weeks, to verify, I can report that the car now shifts as expected, very smoothly.....my only thought as to the initial cause of the problem was that when I first picked the car up from the dealership, I was immediately playing around, a lot, with the auto-stop/start function and all the various driving modes, right from the get-go....I suspect that some driving patterns were 'learned' that caused me problems when driving like my wife wants me to drive all the time - conservatively but not too exciting.......This is speculation of course, but the results are compelling - resetting the TCU fixed my jerky shifting and also seemed to help as to when the auto-start/stop engages and disengages.. To reset TCU on this car, hit the start button twice, (second position) but do not start the car. Once all the dash lights turn on, floor the throttle pedal and keep it floored for 10-15 seconds - With the throttle still floored hit the start button again to turn everything off. Once everything is off, release the throttle pedal. Leave the car alone for 5 minutes for some internal TCU 'magic' to happen.....then start driving normally again giving the TCU the opportunity to get to know you a little better ;o) (You can find many links on the 'net with appropriate TCU reset instructions for your specific vehicle, make, model and year.)

 

This is super helpful for those who have problems. Thanks. I can also add that since it's a wet clutch tranny, it's a good idea to wait until the temperature goes up before you engage in spirited driving.
If you go to temp indicator (3 temp graphs) the first one is the one to pay attention to.

 

This is a variation of the urban myth surrounding transmission "resets". None work, they are all placebo procedures. There is no WIS procedure for "resetting" the transmission control unit. The only way to do this on an MB is to reset adaptations (MB terminology) using XENTRY. Posting MB documentation to this thread would be a basis to revisit the statement.

 

The procedure above may have worked for older transmissions, but as far as I know the only way to properly reset the adaptations with the newer transmissions is as said through XENTRY. For the most part, these transmissions continually adapt. Over time they will adapt to your driving style and it isn't for no reason that AMG states in the break-in instructions to leave it in Comfort mode during the break-in. That's so that it can learn the baseline properly. If you disregarded this, then drive it in Comfort mode for 1000 miles and see if it improves.

I had two issues with the 9-speed MCT in my C63 and they went away on their own by simply following instructions. The first one was that initially I didn't do much city driving. I did European delivery and mostly blasted around the Autobahn for the first 6000 miles, so in the cities it shifted rough and particularly it insisted on downshifting to 1st gear before I came to a stop. This all went away after I did more city driving in Comfort mode once the car had arrived in the USA. The second one was regular jolts after a cold start going from P to R or P to D. This also was my doing by not putting the transmission in P before turning off the engine and instead relying on it going to P automatically. This caused it to never adapt the initial P to R and P to D engagement. There's a TSB for this. After I started putting it in P explicitly it took about a week for the issue to disappear. I now always put it in P myself and it's been smooth sailing since.

 

Legend or not, it is my reality, and it completely resolved my problem.

 

I purchased a 2023 C43 last May. My car currently has 6000 miles. My car is in the shop for a 2nd time right now for the same issue. I experienced the exact same issue as @Venturep described where the car physically jerks the driver/passenger and you can visibly see the car dip in the back when coming off a complete stop between 1st and 2nd gear. The issue is 100% reproducible in any mode (comfort, s,s+). I can take off by easing on the gas or accelerating aggressively, warm transmission, cold transmission, after coming to a full stop at a red traffic light....it doesn't matter how I drive it . I have also noticed a slight jerk when downshifting from 6 to 5. More recently I also notice the car is slow to respond to acceleration at all from a full stop.

The first time the dealer had my car for 29 days with a "PTSS" case open with Mercedes corporate. They "retrained" the car per instructions from Mercedes. It drove better for 500 miles, then the problem came back. I was told Tues Jan 23,2024 that Mercedes still doesn't have the software update and there is no ETA. There is a Mercedes TIPS CASE LI27.60-P-076554 open for the issue.

I am going to reach out to Mercedes corporate and put on some pressure. One more time and Mercedes is taking this car back. Queuing up a lawyer.

 

Mercedes Corporate is the worst branch of any customer service I've ever experienced. I hope you have patience and goodluck.

If I could get back the time I have wasted contacting I'd have never bothered at all.

 

The problem is back, Ndwitt described it perfectly. Making another appointment with the dealer.

 

Just out of curiosity, do you guys with transmission problems ever drive in a spirited manner, like fast acceleration either from the stop or a roll and at high speeds?

 

One of my other cars is a Porsche so I have been known to have a lead foot ..however not with this car....as the transmission shifting mode is too unpredictable. It seems like every time I drive it, it can either be relatively smooth or abysmally bad, very rough, that said mostly it's pretty rough. Something is just not right with the design or electronics, or both. Loss for words re MB quality standards on this model...

 

I have the same issue. The transmission is unpredictable. It is a holly crap let say......it drops the clutch in case of downshifting like a rookie driver.....very disappointed in general about the quality of the car as well

 

Thanks @Ndwitt and please keep us posted

we got the w206 c43 around dec 2023 and we experienced the exact same issues you describned after driving it for a month:

- jerky 1st to 2nd shift, anything after 2nd gear felt fine
- extreme lag on acceleration from standstill, almost like the acceleration isn't proportional at all especially with auto-start-stop (the moment you let go of the brake > engine starts > foot on gas, pressing 30% does almost nothing to the car and if you press it by another bit it engages & launches the car hard)

the auto-stop-start also isn't very intuitive. the engine shuts off when the car is still rolling prior to coming to a complete stop, and when it comes to a full stop, the engine starts again

 

I took the car in again this week because the jerky shift issue came back again. Dealership service refused to fix it for the second time. They said they want to wait for the software update which has no ETA. I was shocked.

Did anyone have the same experience?

 

Mine was in service for the same reason. The problem was mainly that during downshifting for example when I slowed down to a crossroad it was dropping the clutch so dramatically that I was almost faced with my head the front windscreen. In higher shift it was not so bad. ....

So the service said that immediately that it is truly terrible after they tried it. It was in the service for 2-3 days and they said that it had to be "relearned" which is a process which every transmission has to gone through but for some reason mine was not successfully done. So they relearned or reteach the transmission. I asked whether they uploaded any new software and they said that no, there is no new software availabile it is purely about reteaching it....

Now it is much, much better. I would not say that it is perfect but if this had been the case originally I might have not even complained about that just accept it.

 

For the engine shuts off which I was also comlaining about I was told that accoring to the regulations it must be shut off below 11km/h if your leg is of the gas pedal....they cannot change it, they suggest to turn off the automatic shut off function below the start/stop bottom.

 

Agree, same problems, took car in to MB again, April 2024, they had the trans "re-program" itself, did nothing else. Problems still exist and now I have terrible "drop-the-clutch" downshifts, worse than before.....They tell me I have to wait for a MB software upgrade.....still waiting. In the mean-time I just changed the oil at 6000 miles and cannot for the life of me figure out how to get into the Workshop mode to reset the Service A interval. Spent two-hours on the net viewing DIY videos and nothing seems to work, so frustrating.

Also one more tidbit of info - I purchased an highend ODBC scanner (Youcanic ~ $500) to read my diagnostics and after spending hours on the phone with the Youcanic tech support team we came to realize that MB encrypts the ODBC datastream so the only way it can be accessed is by using a MB reader, at the dealership...I'm just beyond belief here!

 

right, I already said in one the threads here that no reader works on W206 and W223. I am not sure you'd be able to reset the Service either.

 

yes I got the same response MBusa is the worst customer service

 

Update - two visits to the MB dealer later regarding the "whiplash" like shifting (wife won't ride in the car anymore due to chronic neck issues) - these are the steps performed to address unacceptable clunky/hard shifting:
Perform Quick Test
Perform Test Drive
Flush Automatic transmission and Torque Converter
Lower Engine Compartment Paneling Center and Rear Parts Remove/Install
Check/Correct Oil Level in Automatic Transmission via Ultrasound (after leak test) on Veh. with Transmission
Adaptation perform (after repairs)
Nontime for Per LI additional adaptation and Valve Flushing
Open Campaign 2024020005 - 23P5498106 RE: Service Campaign Launch Notification
Update SCN Coding for DRVU Control Unit L1
Cause: Perform SCN Coding in DRVU Control Unit (with XENTRY/DAS Connected)

Comments from the Tech:
"test drove vehicle again and vehicle now downshifts smoothly into gear from 5th to 4th but notice hard shifting was now present from 1st - 2nd. Performed additional quicktest and no DTC's present or stored. Found LI27.60-P-076554, LI states that software is in development but to perform remedy steps. Performed transmission fluid level check and it is OK, performed 3 additional valves flushings of the transmission via sds, performed 2 more standstill adaptations, test drove vehicle 2 more miles and vehicle shifts much smoother now.. let vehicle sit overnight and test drove again at cold start and verified that the vehicle is shifting as designed."

For now, shifting is acceptable, but I'm driving very gently (no more Sport or Sport+ mode or hard acceleration) because I DO NOT want the symptoms to return - apparently, all the above is most likely a temporary fix until MB comes out with an update (whatever that means). I will say my current dealership has been very helpful (different from where I purchased the car as they were essentially useless and treated me like an idiot).

BTW - I did figure out how to reset the service interval after accessing "Workshop Mode," (Again this is for a 2023 C43 AMG with the M139 engine.)
To Access Workshop Mode - Steps:
1 – press start/stop button 1x
2 – using the left scroll pad bring up the trip/mileage display
3 – press left “Home” button for 10 seconds
4 – then immediately press left OK button for 10 seconds
5 – then the OK button again for 1 second
6 – The workshop menu will then display
7 – Scroll to Assyst Plus
8 – You will see “For Assyst Plus – Ignition Stage 1
9 – Press the Start/Stop button again (do not touch the brake or accelerator pedal)
10 – You can then scroll through the Assyst Plus Service Interval Reset menu

 

To my surprise today, I was reading the news and one article mentioned c43. I clicked it and it was about a viral video of a man with a new c43 complaining about the transmission. And this wasn't a car website! Seems his video went viral in tik tok. Maybe mercedes will respond? My car has the same issue. But dealer said it is officially normal.

My car has been in the shop 3 times iver 12 months. 2 times for a CEL, 4 days in shop total. Now my seat belt tensioner broke, been in the shop for 17 days waiting for parts. Considering contacting mbusa.

https://www.dailydot.com/news/buy-back-2023-mercedes/

 

Need to ask, how long did the "fix" continue to work. Followed what you laid out here last night, and car is driving much better.

 

I have had this procedure done twice since purchasing the car new in April of 2023. First time the fix lasted about 3-4 weeks. The second time around it's only been 6 days since getting the car back. The service tech said they've had a number of the 2023 cars with the same problem and the duration of the fix just depends on your driving 'envelope,' and that MB is working on a "fix." That said there is no ETA for the fix, so as to how hard they are working on a fix, it's up for debate....I'm still doing all my driving in comfort mode sans aggression....

 

Thanks. Your "fix" that you outline a couple of months ago seems to be working for now. Had it in for service a couple of months ago with no real improvement. Bringing it in again next week. Hoping for a little longer term improvement!

 

My W206 C43 recently had a 12-monthly A-Service, which included a software update on the engine control unit. There have been some noticeable changes to the gearbox and shift points as a result. Note that it's hard to tell exactly what the changes are and what just subjectively feels different to me, but my observations below:

• Gearbox is back in a "learning" period. A few of the shifts, like 2nd to 1st under braking, were initially a little rough after the update when they were not previously. Has been smoothing out noticeably over the past 200kms.
• Mid-throttle acceleration from 1st gear in auto results in more rapid gearing up to 2nd, 3rd, 4th.
• The car tends to a lower gear in highway driving with cruise control on (sits in 6th gear at 105kph, previously it would choose 7th). If I manually select 7th, it will stay there even after the gearbox reverts to auto mode.
• For low-speed driving, such as in a car park, the car selects 2nd gear at a lower speed than it did previously.
• Shift time in auto and manual mode, both up and down, feels quicker. Not as quick as a MB dual clutch gearbox, but faster than they were previously.
• The exhaust is definitely louder, with more burbling and pops when backing off the throttle or at high-rpm shifting.

There’s clearly some changes made in the software update, so if anyone is still having gearbox issues, it’s probably worth asking for the newest software to see if your issues are resolved after the learning period.

I had quite a few items on the service report, but for reference I think the section below relates to the engine/gearbox software update:

SM5065; UPDATE CONTROL UNIT SOFTWARE ENGINE N3/10.
CARRY OUT SM5065; UPDATE CONTROL UNIT SOFTWARE ENGINE N3/10.
REPAIR PER FACTORY RECOMMENDATION.

 

Just made an appt with my dealership, my service rep was not aware of whatever the "SM5065" is. I did have the car in for clunking shifting in August and September of this year and one of the shift points is infinitely smoother (3rd to 4th, and back) but anything involving the lower gears are still very problematic. Have an appt on 11/19 to check into the SM5065 update...thank you