gg_monogram

Hi,

I have a 2020 C43 and last week was the 2nd time I had an issue, I was waiting for the red light and when it turned green, I stepped on the gas and it just rev and the car won't go. I look at the dash, the car was still in D, I did not turn on the Auto Start/Stop and I heard the engine obviously. I had to turn off the car and restart, and it was no issue or anything, no warning light, so I just go and say sorry to the FedEx truck behind me while I was gone.

Anyone had this issue before and what direction am I looking at to troubleshoot this issue? This is the 2nd time that happens since I got the car in March.

Thanks.

gg_monogram

Hi guys, it's me again coming back to the same problem.

Youtube Link:
I was in a traffic jam driving slowly, and I came to a full stop, when I want to resume, my car won't go, Gear is at Drive, no sign of being in Neutral (it chimes when its N), auto start/go was turned off, I didn't engage brake hold either (it releases when you step on the gas anyway). I had to turn the car off and start it again.

Do you guys have any idea what could be the problem? I just finished my 1-year maintenance and I mentioned it to them but dealer couldn't find anything.

Ramsino

This is the first time I've heard of a problem like this. Since the car is still under warranty, you should really bring it into the dealer. They tend to want to be able to reproduce the issue on the spot, but since you have dashcam videos, that may help.

AMGiggity

It has happened to me, once in about 2.5 years of owning it! I stopped to make a left turn on a stop sign and it decided to just do nothing even though it was in D. Had to restart it.

stockbmw

That situation got to be so angry, embarrassing and frustrating

W205C43PFL

Yikes, also the first time I ever heard of this. Super curious what might be the cause as well and really hoping that the dealership can help you solve it so it never happens again as it is extremely dangerous. Sorry that this happened to you, so often too and even worse in stop and go traffic on the highway, that must be annoying especially when the driver at the rear thought you weren't paying attention (therefore the honk) when it wasn't even your fault.

AMGiggity

I don't think it is extremely dangerous, it does not stop out of nowhere, it just refuses to move when it is already stopped, and it has happened to me only once (not sure about others) in more than 2 years. Probably a hard to find software bug. But yeah kind of embarrassing.

Ramsino

Do you notice the RPM needle dropping really low to around 1000 RPM or even lower before the car shuts off or did you come to a complete stop and the needle is positioned where it normally would be and then the car just suddenly shuts off? I'm wondering if the car is stalling cause it's dropping the RPM too much or something.
Have you tried leaving automatic stop/start ON and see if this situation ever occurs?

W205C43PFL

Sorry to hear that it also happened to your car, glad it wasn't really a safety issue and that you and OP is fine when it happened but ya it is annoying, also happy to hear that it never happened to you again afterwards. Thanks for sharing your experience.

gg_monogram

My speed was 0mph all 3 times that happened to me and the rev is not zero, and I definitely hear the engine is on and not hibernated, I have not tried to leave the stop/start on 99.95% of my drive time so I can't really tell if that would happen, but I do know the start/stop resumes pretty quickly.

W205C43PFL

Hmmm, and the dealer said no stored codes right?

gg_monogram

yup i asked, they said the vehicle doesnt have hourly log like that when i told them i have the exact time of occurence.

stockbmw

You show them the video?

W205C43PFL

Hmmm oh well, or maybe they don't have the authority to, I heard our cars have some sort of blackbox similar to aircrafts that if Mercedes needs to access data they could (although I don't know how reliable is that source (of which I heard from), I wouldn't be surprised if we do, for example, they are able to pull data to prove if there is a tune when given authority to on what RPM the engine was at, what temperature was the gearbox and the engine, the brake pressure applied and the accelerator pressure applied, the turning radius etc.)

gg_monogram

especially they have mercedes connect, sos, all these emergency road side services that tells all the condition of the car. well.... guess i ll find out on saturday service. additionally they replaced my wiper and it judders A LOT!

W205C43PFL

Yup exactly, and good luck with the service appointment.

TModelle

I personally think wiper judder was a design feature on the W205. Seems like everyone has had some form of judder to various degrees and can’t completely eradicate it. Quite disappointing for a car at this price level in my opinion. One of my pet peeves about the W205.

DrMattyJK

Hi there. My 2020 C43 will randomly do exactly what you state. Mercedes is "unable to replicate" therefore the problem does not exist.
Did you ever find a fix?
Thanks

gg_monogram

not really, but did serveral software updates on the dealer level, at least it didn't happen since my last reply above. I guess u can go to the dealer and check for the latest software. One thing I can tell is that one software update completely gave me a "new" driving feeling, like accel, brake, and pops and bang, so I knew they must have really updated the software.

DrMattyJK

Right on. That is good to know.

My trans also has a VERY rough 2-1 down shift. Essentially if you get to a stop and ease off or let go of the brake ... THUD. Almost like you are rear ended.
Does yours do that?? I'm trying to get a fix for this.

Other then the trans the car is pretty awesome.

gg_monogram

afaik there is no fix on jockey 2 > 1, the car builds just like that, and we selected AMG, for this reason, isn't that? lol

DrMattyJK

Thanks for the info! My tech said that mine is "the worst" he has ever experienced. Even with reprogramming. They took the driveshaft off and lubricated the splines. No fix.
Bad design. I've owned many high performance vehicles and none have done anything like this...

DrMattyJK

For those owners where the car 'randomly goes into a neutral condition' despite being in drive, I would encourage you to report to the NHTSA as a safety issue. It's a programming glitch that occur under certain conditions. They won't work on a fix unless enough people complain or they are forced by Transport.

https://www.nhtsa.gov/

W205C43PFL

How wide spread is this issue though? Any insight on what might it be, when did the affected owners got their TCU last updated? Mostly it is a software issue I think, unlikely it is hardware?

DrMattyJK

I suspect this is not that common. When you dig into it though, it is a known issue. It’s quite jarring and sends you scrambling like an idiot. You totally don’t expect it. A car should not do this.