100stars

I just purchased a new 2021 CLS450. It now has 250 miles. This is my first turbo engine car after a very long time (my last one was Mazda RX-7). long story short the engine caught on fire and I never purchased any turbo cars anymore. I have a 2018 Lexus LX570 and the V8 engine is buttery smooth. The Mercedes starts good but after 2~3 minutes in idling shakes for no reason. It does this a few times. Also on the road at the traffic light sometimes same happens. Has anyone experienced this?

FrostedGlass

Could this be the ECO start/stop function? It will automatically switch off the engine if vehicle is stopped and certain conditions are met, and then automatically restart the engine as needed. This is rougher and more noticeable in some vehicles than others. It helps MB keep their fleet wide fuel consumption stats down.

There should be a button on the middle console to disengage. By default ECO start/stop is engaged on startup and the button shows a green light, pressing the button turns off ECO start/stop and the light goes out. The symbol on the button is "A" with an arrow around it in a circle. This feature is documented in the Owner's Manual.

100stars

This only happens in the beginning few minutes. On the road, all goes well including auto start-stop function. Then if I break the journey the car will do the same vibrations and then going smooth after 2~3 minutes. I can take it to the dealer but with my personal past experience with my 2014 e350 Mercedes, I do not want a dealer mechanic touching the car unnecessarily.

petee1997

Then the vibration will not go away and it’s notbnormall

kdub

I have the exact same issue on my 2022 which I bought October 2023 brand new. I posted a different thread - didn't see this one. I took it to the dealer and they ran diagnostics but did not find anything. I feel like the problem went away temporaily after long road trips - but came back with around the town traffic. I noticed it again yesterday.

lena44

Did anyone happen to find out what was wrong? This is currently happening to me and the dealer says they can’t find anything wrong.

100stars

My car has been at the dealer for the last five days. They are still trying to figure it out. I will update what they find out.

MB2timer

My first suspicion is loose hardware, fitting or connection.
Sometimes when hardware is loose, it can’t back out all the way from installation interference.
Anything loose will have a harmonic with engine vibration.
It could set up this harmonic vibration at certain engine speeds, in this case idle.
It might go away as the engine heats up, and seats better in its recess.
The best way to ferret out a vibration like that is to use a stethoscope and replicate as best you can the conditions where you routinely observe it.

Helo pilot

I have a 2023 CLS450 and had a similar issue and took to my dealer in Oklahoma City. The shop foreman check my car and suspected it was the firing timing. He reset the timing and the problem went away. I only noticed shaking in the steering wheel when the RPM at an idle would go from 500 to 800 rpm. I can provide you with the name of the shop foreman if you need. Send me an email.

Regards.