mbsl550.19

So I bought a 2021 S580 just lasts Thursday. I went out for lunch
today and when I started the car up again I got this message.
"the 12 volt on board electrical system in malfunctioning" on
the left display. The main 12 inch display said:
Stop the vehicle in accordance with driving conditions etc.
Do not continue driving, shut off the vehicle.


Yikes, less than 200 miles, car 3 days old. Called the dealership the
SA needed to consult a mechanic and told me to drive the car to the
dealership. Pretty depressed that an issue like this happened after
200 miles on a $140k car.


Anyone see this before? The SA didn't even know that the MB had
3 batteries, 48 volt, 12 volt (starter in the front) and the 12 volt in the
trunk for everything else.

W205C43PFL

Sorry to hear about your issue, the issue you described is very similar to what another forum member here is experiencing, please take a look here:
https://mbworld.org/forums/s-class-w...n-t-start.html
https://mbworld.org/forums/cls-coupe...ml#post8411930

AWTX

I use ctek battery charger for an entire weekend on the battery under the hood and it keeps the healthy green light. Think I need to find trunk battery and do that too?
My car was produced in February and didn’t arrive at dealer until July and delivered to me in August. I’m thinking that’s a long time without use but I don’t know if it matters.

E55Greasemonkey

Check the build date on the door jamb VIN sticker. Many of these cars sat for months before being shipped to dealers. Lot rot includes rusty brakes and dead batteries.

mbsl550.19

Thx for the info. I hope it's just the 12v starter battery. Car did drive to the dealership
and everything thing "seemed" to be working.

mbsl550.19

No charging both batteries only requires that you charge the battery in the engine bay, the "stater" battery.

mbsl550.19

Good point. I would but the car is sitting at the dealership.

You know you buy a $140k car and they give you a C300 sedan as a replacement. Not a knock on the C300 sedan though. Geez.

W205C43PFL

That's sad, I am sorry to hear that. The loaners I get are usually one class below or the same class here in Canada (provided by Enterprise), I am not sure if it is different in the states. Unless (which I believe is more likely), they are selling the loaner stock in the states (if the loaners are owned by the dealership and not Enterprise) so they don't have enough of these courtesy service loaners left for their intended purpose.

js_cls

Be thankful you have loaners, I am hearing stories of people from various brands whether it be Porsche, BMW, MB, or Audi that because of the current used car market there is now a loaner shortage too at many dealers since customers were buying loaners when they couldn't get new cars.

hyperion667

Oh not another one, sorry to hear this.....makes my heart drop. I'd be pretty fawking livid! GL to you.

W205C43PFL

Ya I am actually but at the same time I don't go to the dealership anymore for my car (my warranty expired) so not like it matters. Plus, I rather not have to go to the dealership since for every problem I face with my vehicle they say they can't duplicate and end up breaking something even like scratching my trim pieces and worse was dinging my door. That being said, since my dealership is owned by MB Canada and the loaners are provided by Enterprise, I doubt the dealership can sell them.

js_cls

My comment wasn't specifying you individually, especially since your situation in Canada is different and you have rentals supplied by enterprise, but was mainly aimed to OP. Most US MB dealers have a system where once a car reach a certain milage and/or 90 days of loaner service it is eligible for sale. I was just saying that OP while he did get a C-Class as a loaner should be glad that he was able to receive one at all as they have become very scarce among different luxury brands and dealers due to the current shortage. Many dealers have cut their loaner fleets in half or even changed their rules for who can receive loaners.

W205C43PFL

I see. Thanks for explaining how loaners are turned into saleable stock in the USA. I learned something and good to know how MB dealerships does things across the border.

190Efan

I'm very sympathetic to your frustration but think it's highly likely that the months of sitting is the culprit here. The new MBs have so many more electronics that continue to run and thereby drain the battery regardless if the car is being driven or not. Hopefully now that the battery is being addressed and the car will be used regularly from here on, that should solve the issue.

ColeBlooded

The cars that sat were maintained at the vpc. My LS500 was built a year before I bought it and didn't have any battery problems.

My S-class has been at the dealer for nearly a week troubleshooting the battery problem.

mbsl550.19

So some very good news. Apparently someone had left the lights on and weakened the rear (trunk) battery.
BTW recorded by the ECU. I guess there is a mode on the lights where the car cannot override it
and shut them off. The light on the S580 is on the drivers door, not the dash. And driving it did not
charge it up enough. So the dealership just recharged the battery. Will pick it up tmrw.

All good, so relieved.

W205C43PFL

Good to hear but that is the first time I hear dealerships pulling data like that to diagnose a battery drain issue, I don't think the dealership have access to the car's blackbox for example, or do they?

mbsl550.19

Me either. Maybe had some data that said the lights exceeded some timeout? I'll ask more details tmrw when I
pickup the car. I know Porsche keeps track of your revs and those that are over range. I was so relieved that
it wasn't a 48v issue my brain went blank.

W205C43PFL

Happy to hear both you and forum member ColeBlooded have their car fixed today. Hopefully that means MB found the "cure" for the 48V battery disease.

absent

Wow!
Makes me appreciate and respect my dealer even more, in the past 20 years or so of being their customer, never had a loaner below S450.
Even my GLA250 driving son (before he totaled it) was always getting E53 or GLE43.

ColeBlooded

Wow. They gave me a glb250

Socalsteve

My dealership sold all their loaners. They pay for uber or you can get a rental through Enterprise. Not a clue what car that may be given the issues with car rental companies.

190Efan

I figured it was likely something on this order. Glad your dealership got to the bottom of this. Now on to many happy miles with your new S class. Enjoy!

Radman991

I had a similar post a while ago about putting a Ctek charger on the main battery and thus charging the auxiliary battery as well on my 2018 S560. I received many replies that charging the main battery has no effect on the auxiliary battery and if you try to separately charge the auxiliary battery, it would void your warranty. Not sure if this is true. I had the charger on my car during the summer months while stored in my garage and when I first drove it again in the early fall, the auxiliary battery had failed. I had it replaced under warranty. Main starter battery was and still is fine.

Streamliner

One of my all time gripes. I wrote to my dealer GM a couple of years ago: “You bring in a $29K CLA250 for service, they give you a $29K CLA250 loaner. You bring in a $130K S560 for service and they give you a $29K CLA250 loaner.” As an older guy who is over 6’, I found it difficult getting in and out on these tiny vehicles. Even a C Class is a pain in the rear.

The GM agreed that it was pretty ridiculous and promised that from that day on, I would receive an “E Class or larger loan vehicle.” The squeaky wheel gets the grease. Complaining works sometimes.