Anyone have problem I have had the car for 7 months and it has been in the shop over 3 month Battery keeps going dead

 

Welcome aboard

 

moved to W206 AMG forum...

 

I'm hearing so many quality issues with the new C43.

 

Tons, not just the C43 but all across the lineups. Battery issues and tech gremlins galore. Add the AMG component which makes the car so much more complicated and you now have an appliance on wheels. More tech than car. Look at the EQ lines, values plummeting. C43 values likely to do the same, too early to tell on the 63 but my money says they follow.

OP should lemon it.

 

i took delivery like 2 weeks ago and haven’t had a problem knock on wood. So far im loving my c43 sorry to hear your having issues.

 

My C43 stopped on the first day with electric problem, the dashboard and right doors there were noise which was quite annoying. In the 2 week the air ventilation stopped to work, it have to be software upgraded in the service. Now I am using it. Out of the 4 weeks it was in service for 2 weeks
Anyway the transition is bad in general during the downshifting and the fuel consumption is 20% worth than my 3liter 6cylinder BMW.
Lets hope that it will be better and better....

 

I've had a similar issue. MB have tested the battery and say it passes all tests. I don't think it's a battery issue, rather it's charger or software related.

Does anyone know exactly which module is in the trunk, to the right of the battery? Silver box with heatsink fins in the pic below. I suspect it's a DC-DC converter so that the 48V generated by the ISG can be reduced to 12V to charge the car battery, but I'm not certain. I've noticed that whenever I get notification of low or critical battery this module is very hot, even in cool weather when the car has been turned off. I've also noticed that the 12V internal battery temperature increases significantly when I get low battery warnings (viewed from the Workshop menu on the dashboard).

 

I purchased a 2023 C43 in Jan. 2024. During orientation on delivery the Mercedes Me app told me that the battery was critically low. I didn't sweat it, took it home and put it on a charger. Next morning still dead (sorry I cannot remember exactly what I did and saw). Took it in to the dealer, they said the battery checked out, they charged it and I took the car home.

The next week I took it back to the dealership to do a ceramic coating (not really what I thought it was... I should have researched more diligently). During this process they ran the battery down again. That evening it would not take a charge at all and at some point the check engine light came on. Took it back to the dealership and they told me that the battery again checked out but there is a software issue they're working on. Topic Number LI54.10-P-076820. They advised me to keep the car locked in my garage each night (I am not accustomed to doing that and had not been) and to keep the keys "far away" from the car and they would call me when the fix was ready. Since then I have not had any issues.

Last week they notified me that the issue has been resolved with a software fix. It is today at the dealership getting the software update. Hopefully this will get it sorted. HTH.

 

I had the same battery issues. It turns out there was an issue with the door locking components on all my doors. It caused the car to not completely shut down when locked. So it drained the battery. They replaced all 4 components and it works fine. They also said there was a known issue that causes the same battery drain if you accidentally press the fob door lock button more than once. They said Mercedes is working on a solution.
Hopefully this helps anyone struggling to find the issue.

 

Yes, same issue. The bulletin I saw (LI54.10-P-076820) does mention the door control unit: "Cause: The door control unit (N69/x) may sporadically keep the interior CAN bus awake."

The bulletin mentioned two door controller item numbers, they must have replaced yours with different items. In my case they tell me that the software update fixes the issue. I also got the advice to not press the fob lock button twice. I forgot to ask them if the software update remedies that.

 

The same bulletin LI54.10-P-076820 has an update (ver. 7) that came out in June 2024.
I took the car to the dealership because it kept giving me those low battery messages.
Hopefully this version will fix the issue.

 

I also had battery partially charged and critical after the car was not used while on holiday.
It was checked out at MB dealership and tested ok and a 0.02 amp drain which they say is normal
As the car still started I have just put it down to “ One of those things”

 

Looks like MB denies that they are making appliance on wheels https://www.carscoops.com/2025/04/me...s%20the%20plan.