1Gunner

Really?! So this problem begins and ends with driver inadvertence in your mind?

Funny how another German car with 600HP can be smooth as silk in sport+ no matter how inadvertently the throttle is depressed .....but a measly 372HP sedan will kick and buck like a rodeo horse with the same driver on occasion.

I stand by my comment, the throttle mapping is far to sensitive on the C43 in Sport+. Shame on Mercedes for not rectifying such a simple solution.

SteveE400

I don't think this is a driver-induced issue at all. In fact, there may be two separate issues in play. Please note that I do not have an AMG model, but I do have an E400. Some things in common with the C43 and GLC43, namely M276DELA30 twin-turbo V6 engines.

I think that the "dead spot" when you let off the throttle and then step on it again - only to find that there is no response, is most likely an issue with the engine/transmission control systems and software. The car "thinks" you are going to stop. Then when you don't stop, it takes too long to get back into motion. This has been an issue with many "drive-by-wire" throttle implementations at least since my 2001 LS430. Some are worse than others, and the MB is one of the worst I've driven. Nobody has a real fix for it, and MB will only focus time and money on it if enough people complain.

The second issue I note is what I call "surging." This is when you step on the gas from a dead stop and hold constant pressure on the accelerator, but the car accelerates, slows, then accelerates again -- as others have said, it feels like a novice driver with a manual transmission. This MAY be related to the turbochargers and their pressure management hardware/software. The turbo's may be over-boosting, which causes the waste gates to open and bleed off excess pressure to the atmosphere. When this happens, acceleration falters until the system catches up and the boost level is again within safe parameters for the engine. In my car, this happens more often in 'E' mode than in sport (in Sport mode, it quickly accelerates past the problem zone). The only solution I have found is to use less throttle when pulling away from a light until the engine gets to about 1800 RPM, then after that it seldom happens. Driving these cars smoothly is not easy.

This may all be related to the combination of the turbos with the higher performance intent of these cars, as I do not notice either of these anomalies with our normally aspirated 3.5L GLK350.

jonathan358

The acceleration (Force) of a 600HP car and the C43 is not that far off. Give or take ~0.5 seconds of 0-60 times, the AWD C43 can cause Driver Induced Oscillation just as easily. Physics acts the same in both regards.

edit: This is not to say I disagree with your statement about it being a throttle mapping problem; it very well could be. But because you brought up HP, it seems as though the were inferring it to be the difference in HP.

agchenry

This topic has come up be fore (exteme spot+ Bunny hop tread I think) and the op in that thread got problem solved at dealer with a software update

DRLC43

1Gunner

It's closer to 2 seconds difference 0-60 between my 991.2 Porsche Turbo S and my C43, which is HUGE... both cars are twin turbo, both are AWD. The C43 is not even in the same zip code as 991.2 Porsche TTS in quickness (acceleration)

The person I responded to was stating the C43 issue was a byproduct of quickness.

DRLC43

jonathan358

Shouldn't rule out driver error so quickly. There are a lot of other factors in play as well such as suspension, seats, seating position, ect... (Just the overall handling of a car)

Although the Porsche Turbo S is hands-down faster, the C43 is still powerful which can cause users to have this problem. It also weighs nearly 500lbs more. Therefore, the force of a C43 is higher relative to the power:weight ratio of the Porsche.

Again, I am not ruling it out to throttle mapping/transmission problems as there have been many cases of this happening.

1Gunner

Saying C43's throttle issues it's purely driver induced is erroneous in my view.

Was only using Porsche as it's an example of an extremely FAST but also silky smooth on delivery no matter what situation, whereas the C43 is not anywhere near as fast or quick in direct comparison, yet it still exhibits this crazy throttle jouncy tendency in S+.
Being a PCA instructor (and a schedule A race license holder) who owns both cars, I'm pretty confident my seat positioning and throttle control might be above the average enthusiast and yet I've gotten this bucking and rocking in the C43 occasionally. I drive around it now, but my point is... why should I need to make an effort to do this when MB could adjust throttle mapping to correct this annoying Sport+ issue.

A simple tweak would make the already enjoyable C43, even more of a driving pleasure than it is already.

coladin

I have an appointment coming up for my C43 transmission issues. The car slips like a burnt clutch, won't shift at redline in 1st(5000rpm), get strange error codes in red. I have been lucky enough to tape it while driving (I know, but on a deserted street at night) as it seems to happen only once a day. The first time. After that , it is good to go typically. I was told I had a software update a month after I bought it and brought it in, but it seemed to work only for a little while. Ultimately, this transmission is ruining the experience only if you like to plant it off the line, which for a car like this, one would like to be able to do that.

Big Goober

Yep, going back in also. We’ll see what they have for me this time.

turismo1

I just bought a c43 and im having this issue that you guys are. I like driving in S+ because of the exhaust, but this rocking back and forth is annoying as f***. Usually this happens when Im at a dead stop and I accelerate at 20% throttle. Most commonly im doing this when i'm making a turn, so im not going to mash the throttle and get the car to shift up fast or i'll probably activate traction control or spin out a bit (i assume).

I dont have the rocking back and forth if i give the throttle 5-10% or give it 100%. Is there a way to avoid this issue from what you guys have seen so far?

FirstMBAMG

Turismo, there is apparently an update that MB can do to adjust for this but they won’t automatically offer it or look for it (there is a recent thread around here about it). As far as solving in the meantime, it is part of the automatics ability to handle shifting gears in a tightly tuned sports car, and they didn’t do a great job when the car is trying to downshift (like making a turn or rolling through a stop), and you hammer it. It’s not great at reacting. Very easy “fix” is to let off the gas slightly, give the car time to understand it’s going the other way. OR better fix is to shift to accommodate the flooring it, that will alleviate it.

1Gunner

Same happened to me several times in same scenario... VERY annoying indeed for a car of this calibre to behave in this manner.

Here's a work-a-round.... When in Sport +, from a dead stop upshift to 2nd gear before you start into the intersection. There's lots of torque with the turbo engine that it pulls nicely in 2nd gear from a dead stop.

Nc43

C43_1995

Just chiming in to say that I have this problem too, Sport+ light gas in 1st or 2nd makes it buck back and forth wildly. I have an '18, so they obviously haven't updated the new models yet. Going to go to the dealer soon, as it's started happening (albeit more rarely) when I'm in Sport mode as well.

MBkent

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jonathan358

I hear that you can upshift manually to stop the jerking.

leojhartiv

I got this solved via the dealer. Mentioned this thread or another with references to a known TSB and they upgraded the software/firmware/whatever. Haven't noticed a problem since.

removedCFGaccount

MBkent

Racechip was in Sport or Race mode when it happened

MBkent

Thanks, will keep monitoring before bringing it in. Finger crossed it doesn't happen again.