Shlick96

The 725 9-speed AMG Speed shift has the Trans control unit integrated with the valve body so the TCM and calibrations/software are ruled out.

Bbossy12

My GLA 250 2018 is giving me the same error. The only difference with mine, is that the dash will go black then turn back on then go black and turn back on a few times while driving. After a few rounds of doing this, I eventually will get the same error as you transmission failure stop. I end up having to pull over put the car in park then I can put the car and drive again. This only fixes it for a small amount of time before it happens again.

RavenM6

Sorry to hear you’re going though this. So far mine has only had the transmission malfunction error happen when the car is in reverse. It freezes and won’t let me go into park, drive or neutral without restarting. I’ve only put on a couple hundred miles since the last time it happened but it’ll be going back to the dealer on Wednesday.

RavenM6

That’s a good question. The dealer never shared the fault code with me and I didn’t think to ask them for it. On Wednesday when I drop of my car again, I can ask if they can provide that to me.

Shlick96

definitely do so as this is an important key to diagnosing your problem correctly! I can search some code set criteria and see the thresholds it takes to manipulate the problem in your car.

untamedd

hey just wanted to confirm that you are saying you restart the car while still in reverse given the transmission freezes?

DrMattyJK

I have a 2020 C43 AMG with the 9 speed. Randomly after coming to a stop, the car will not go after I press the accelerator. Just as if it is neutral. No trouble codes come up.

the tech implied there are known issues with this transmission but Merc official response is cannot duplicate or other vague response.

Curious if these trans symptoms are part of a bigger issue they are having difficulty sorting.

RavenM6

Yes, I have to kill the engine while it's still in reverse and restart, as it won't go into neutral, drive or park.

I took it back the dealer this morning. They gave me a loaner but likely won't have any answers until after Christmas. My car's been in the shop for a good 2 months out of the 16 months I've owned it for this transmission issue. And that's not including today's drop off which I'm guessing will be another 2 weeks if I'm lucky .

W205C43PFL

Oh no : ( I am sorry to hear that.

RavenM6

No real updates since I dropped off my beast for the 3rd time regarding this issue. That was over a month ago. The holiday season got in the way, and they were trying to get answers from MB Germany on the issue since the start of the new year.

My S/A called me this morning and said that since the last transmission malfunction code is a stored code and not an active one, they don't really have any way of diagnosing the problem until it happens again. They are wanting to know if I'll give them permission to install a data logger in my car so they'll know exactly what's causing it the next time it happens. I'm not sure I'm comfortable with a tracking device in my car, so I told them I needed some time before I give or don't give my consent on this. What do you guys think?

untamedd

honestly data logging is the way if you really want them to get to the root cause and get rid of it for good

Shlick96

^Agreed, seems like they had you on the back burner for some time since they couldn’t figure out the root cause. I would allow the data logging as well. It’s the only way at this point. What is the code stored? We’re you able to at least get that info out of them?

RavenM6

Thanks for the input guys...yeah I think I'll go ahead and give them consent to install the data logger.

My S/A didn't provide me with the actual error code, I'll try to get that info from him tomorrow.

W205C43PFL

Sincerely hope this time it really helps them solve it so you are back on the road with a problem-free car. I believe your vehicle also have remote diagnostics (the form that is used to instantly and remotely read stored codes) from factory, not sure if that is region dependent though.

W205C43PFL

Here is an example of remote diagnostics: https://mbworld.org/forums/c63-c63s-...ml#post8607131
and here is an explanation by forum member superswiss: https://mbworld.org/forums/c63-c63s-...ml#post8610442

RavenM6

Thanks, I'm really hoping this issue gets resolved once and for all.

Apparently the data logger isn't a stocked item, so they're ordering it from Germany which will take another couple of days. I'll probably have my car back sometime next week and at that point I can finally get those bumper scratches repaired.

W205C43PFL

Ouch I forgot about that too, hopefully that gets resolved to your satisfaction as well.

Shlick96

Fingers crossed they get you fixed up! Very curious to see what the root cause of all your problems were at such a low mileage. Especially considering the entire transmission was replaced with the control unit and programmed,and you still have problems! Keep us updated.

RavenM6

I’ve been really busy so I haven’t gotten around to updating the thread. Dealer called me last week and explained they had instructions from MB mothership to load a new transmission software on my car. They’re 99% sure this would solve the problem once and for all. MB has also offered a buyback in the event the issue surfaces again. My dealer will also be submitting a claim to MB for the 3-4 months loss of use I endured related to the transmission issue.

In the meantime, I dropped my car off at my body shop to get the bumper damages fixed, after which it’ll go to the tint shop to reinstall the front bumper PPF. I have less than 4.5k miles on the clock, it’s still under full warranty for the next 4.5 years so I’m hoping to finally get to enjoy my beast without any further issues 🙂.

Shlick96

Thanks for the update. Glad you got sorted out! But if you want my opinion I think your dealer is full of it. If they replaced the transmission, the mekatronic control unit in the transmission would have to be loaded with the latest software from Xentry. So I’m curious to see if the repair will hold up! Best of luck and keep us posted if anything!

W205C43PFL

Hopefully it is a custom software version specifically developed and adapted to fix the issue OP is having after OP authorize the dealership to use a tracking device to help pinpoint the issue. Glad to hear they filed a claim to refund the months when the car wasn't in OP's possession, it only makes sense. Best of luck to you OP, I too wish that you can finally enjoy your car once and for all.

Serhan

It is good to hear that they are fixing the issue. When MB did the GLB transmission software update and it was nearly 8 months later after I first reported the warning. So far I haven't got the warning after transmission software update. MB should have checked the software initially also... Even 2022 GLC300 that I had as a loaner had a wheel vibration issue at the bumps/cracks and MB service told me that it was a software issue...

RavenM6

Thanks guys..so yes my SA did say that they got a custom coded software for my car from MB headquarters. Whether or not that’s true, I don’t know but they’re very confident the issue has been resolved.

Another week or so, and I’ll have the paint and PPF completed. I plan to take full advantage of the gorgeous spring weather that’s about to come our way, and finally let this shackled beast out of its cage!

W205C43PFL

It is mid-week already, hopefully the dealership will be taking care of you shortly if they haven't already.

RavenM6

I got my car back from the body shop last Thursday after the front bumper re-spray. In my opinion, they matched the paint darn near to perfection. They also fixed the scratches on the black plastic trim pieces of the front bumper so I'm very pleased overall with how it turned out. I was going to drop it off to the tint shop to get the PPF re-installed, however the tint shop owner strongly recommended I wait at least 10-14 days until the paint is fully cured. My body shop said otherwise, but I didn't want to take any chances so I won't get the PPF done until next weekend. Once that's completed, I'll submit the paid invoices to the dealer for reimbursement.