So...wifey took the vehicle to the store, which is 3 1/2 miles away. Vehicle has 318 miles on it and is on it's first tank of gas, since we bought it April 25, this year. Wifey took it out last Saturday for a good 75 miles, so the battery should be charged up and good to go.

Wifey grocery shops and gets back in the car. Unlocks it, opens the trunk, tosses groceries in, and hops in the driver's seat. Proceeds to push the brake pedal in and push to start. She said the screens freaked out and were flashing between the home screen, blank, and blue. Then the screen behind the steering wheel flashed "depress the brake pedal before you put it in gear" or something similar.

She turned it off, got out, locked it and waited for a few minutes.

Then she got back in, turned it on and it started and the engine turned itself off. Then (this is quite the kicker) the convertible top let itself open and tried to shut itself again, but didn't get completely shut, leaving about 2" to go and the windows all partly down. She shut it off, got out of the car, left it unlocked and called me to come get her.

I rolled down there about 5 mins after she called and sure enough the car was "on" but the engine off, the convertible top about 2" open, windows down a bit and the CEL flashing. It started (engine) and I drove it home with the CEL symbol on. I got the convertible top down the rest of the way in the parking lot before I drove it.

Just went out to the garage, it started fine, but the CEL symbol is still on. Meh...gonna have MB come get it tomorrow I think and drag it in for some sniffing. The app says the MBUX software does not need updating and is current as of the day we drove it home (4.25.2025).

Just gee whiz stuff here, in case anyone else comes up on that scenario and things freak out on you (or wifey). More later as I plan to check it out tomorrow and maybe take it for a quick spin around the hood for a few minutes to see if the CEL goes out first.

(Maybe I should have stuck with the 911...LOL)

 

I don’t think it helps keeping these vehicles parked for long periods of time with no use. I drive mine often. Not everyday but at 10k miles in one year now. Zero issues. Runs great.

 

Not what you want from a car that's basically new with so little mileage. This was one of my concerns about going back to MB. My wife's previous 2018 E400 couple only had minor issues. I know MB's reliability has gone down since we purchased that car.
I hope we don't experience this type of issue with our 25 CLE53.
BTW,I just realized that those red reflectors in the doors don't light up when the door is opened. How cheap. That was one of the issues we had with the E400. Those kept falling out (in both doors).
I finally used clear caulk on the rear of those lights to keep them from falling out.

PHXATC, keep us updated on the repair of you car.
Good luck.

 

@utsteve98 I agree with your statement that they probably do better being driven more often. That said, there is nothing in the owner's manual or a contract that says I am forced to drive the car in order for it to perform as expected. My 911 sat for many months unattended with nothing but a battery tender on it and never had one iota of a problem. I know, your RR is driven a ton and you've had good luck driving them a lot and that is your use case, which is perfect for you. Me, not so much and yet I have the same expectations out of a car, any car, to be performing as intended no matter how many miles, how often, or how one keeps the paint polished up.

@dudley07726 Wilco. I went out just now and started her up and the CEL is still on. I happen to know the service manager at Naples MBZ, so will call him after I call the roadside assistance number. More to come. I'm sure it's a nothing, but meh...I don't have time to pull the battery cables and let her sit for a few hours, then try again. Lord knows, if I drive it with the CEL on and something catastrophic happens, they'll blame me.

 

I just dropped off my CLE 53 this morning at MB Naples to fix very minor issues.

 

Ours should be there in a few hours. Glen was the SA we were assigned. We actually know the Service Manager there when we had our Porsches serviced at Porsche Ft Myers.

 

Seems like keeping the starter battery charged is a must for these modern vehicles, they (the modules) are too sensitive to voltage swings.

 

Here is the kicker that y'all are missing. She drove it Saturday (4 days prior) for a healthy 2 hours and had zero issues. I keep it on the battery tender and everything shows just fine.

I've seen batteries with low voltage do some wild stuff, however, unless it is a dead cell in the battery and hiding itself, the starter battery is just fine.

I am interested to see what the code they pull out of there is, when they get back to me.

 

This is distressing to read. I am picking mine up next week. I was reluctant to get a new MB that has everything on screens. My 2020 C43 screen went dead once or twice but a restart fixed it.

If you’re letting your car sit weeks at a time, then I think you put the car in hibernation mode (or something to that effect). I did that with my C43, which I could only drive every few weeks (living in a large city, I don’t / can’t drive regularly).

Hopefully this issue gets resolved ASAP - please keep us posted

 

My fear was MB being too focused on the development of MB OS (as seen on the new CLA) and therefore neglected the software on these cars, MBUX 3.0. nothing updates won't solve, as long as they acknowledge the issue.

 

I don't think you should have to keep it on a battery tender if you just drive it once a week, let alone every 4 days.

 

I’ve had the CLE53 for about 9 months. I’ve never used a battery tender.

 

PHXATC - what Battery Tender model do you use?

I have a spare 12V 1.5-amp Battery Tender and am wondering if this will work.

 

Get the CTEK one, since many brands like Bugatti even just use CTEK and rebrand it: https://mbworld.org/forums/coupe-roa...ml#post8548131

 

@Rocketman1980 I will check this evening or tomorrow and give you the model number. Wait...I can go check Amazon...
This is the one I use on the Lithium one in the Cayenne and 911 If it had to purchase a new one, I would look for a 10amp one, instead of the 5amp one (first link).


Initial report from the SA:

The "center stack" (MBUX infotainment) needed an update and was continually trying to download it either OTA or from the house (parked in the garage) and was not able to finish the download. He surmises that since the download was in progress, for too long he said, that it was a parasitic drain on the starting battery, which then snowballed into other weirdness. The convertible top opening and then closing on it's own he thinks was related to all that and caused a sensor (or two) to wig out. They are trouble shooting all the error faults and codes and should have it done by tomorrow. Nothing major, thank goodness, however plenty of codes thrown and the tech is troubleshooting all of them to ensure they're corrected and not something else other than the initial download hiccup.

More later.

 

[QUOTE=PHXATC;9186932]@Rocketman1980 I will check this evening or tomorrow and give you the model number. Wait...I can go check Amazon...
This is the one I use on the Lithium one in the Cayenne and 911 If it had to purchase a new one, I would look for a 10amp one, instead of the 5amp one (first link).


Initial report from the SA:

The "center stack" (MBUX infotainment) needed an update and was continually trying to download it either OTA or from the house (parked in the garage) and was not able to finish the download. He surmises that since the download was in progress, for too long he said, that it was a parasitic drain on the starting battery, which then snowballed into other weirdness. The convertible top opening and then closing on it's own he thinks was related to all that and caused a sensor (or two) to wig out. They are trouble shooting all the error faults and codes and should have it done by tomorrow. Nothing major, thank goodness, however plenty of codes thrown and the tech is troubleshooting all of them to ensure they're corrected and not something else other than the initial download hiccup.

More later.[/QUOTE
There is no need for you to have a trickle charger on the car with normal usage. And I don’t mean storing it for the winter.
when I lived in NJ, I stored my nice cars for the winter and used a trickle charger on it.

 

I already have the Mercedes-Benz 4.3-amp charger/maintainer but I installed it on my ceiling over where the CLE will be parked for the six-month winter period.

So I did purchase the CTEK charger/maintainer for the summer months. I have other toy cars I also drive so the CLE will be on the CTEK while driving the other cars.

I am a firm believer in using a charger/maintainer on any new car for even short periods (weeks) as well as the winter hibernation. Too many electronic gizmos always running in the background.

Thanks for the information.

 

I, too, most always put the battery tender on the vehicles if we aren't driving them for a week or more. It's just smart and easy. We don't drive much, live in a golf cart community and have a golf cart for all the errands we need during the week. We have two cars and alternate between the two, so one might sit for 14 days without being fired. I agree, there are too many electronic gizmos and parasitic sucks on modern cars, so to keep the battery happy, I just plug the tender in and never worry.

I might not "need to", however it is my cheap insurance for how I use my vehicles. I probably replace my tires too early as well, due to the calendar and date codes, versus the tread wear, however that's what I am comfortable with and my choice. (my car, my choice....HAHAHA...had to) The 2022 911 we had used to get snarky after around 16 days of non-use, however with the tender, she was happy as a clam and never freaked out. All my cars spend their lives in an air conditioned garage, like princesses, so heat isn't a factor either.

Hopefully we get the car back tomorrow and I will provide the synopsis and any quips of knowledge I get from the Service Advisor.

 

Picked up the car. Our SA said @dudley07726 had already paved the way with a few questions. Good job! : )

Here is what was written as happening and what was corrected:

BOTH SCREENS FLASHING COLORS - CONNECTED SDS AND BATTERY TENDER. UPDATED HEAD UNIT SOFTWARE. UPDATED DRIVERS DISPLAY SOFTWARE. UPDATED CENTRAL DISPLAY SOFTWARE. VERIFIED CORRECTION OF COMPLAINT.

CABRIOLET TOP OPENING/CLOSING BY SELF - UPDATED UPPER CONROL PANEL SOFTWARE. UPDATED REAR CONTROL UNIT SOFTWARE. VERIFIED NORMAL OPERATION.

CEL - FOUND FAULTS FOR COMMUNICATION ERROR IN EZS AND PTCU. UPDATED SOFTWARE IN PTCU. UPDATED SOFTWARE IN DRVU. UPDATED SOFTWARE IN ALL 4 DOORS CONTROL UNITS. UPDATED SOFTWARE IN MFK. UPDATED SOFTWARE IN STEERING CONTROL MODULE. VERIFIED CORRECTION OF COMPLAINT.

 

I didn’t write that I spoke with him yesterday. I didn’t want you to get mad. My car was in there for very minor stuff and when I went to pick it up, I spoke with your SA briefly. He said it was all software. He also said you need not have to use a battery tender with normal usage. I’m sorry as I was curious as we both have the same car. Just in case the same thing happens to us. I told him that we met on this forum. Glad it’s all fixed for you.

 

HA. I could care less. It's all good and solving problems and sharing knowledge is better in the long run. I don't get mad about $ h i t like that.

And of course it POURED on the car on the way home too. Washing her is in my weekend future!

 

There are two electrical system in the mild hybrid Mercs.

48 volt;
Combination Starter/Motor/Generator bolted to the back of the crankshaft.
Water pump.
Air conditioning compressor.
Supercharger on the 53s only.
12 volt;
Everything else.

There is a bi-directional converter between the two systems in the trunk perhaps??
This converter normally powers the 12 volt system as there is no 12v generator.
(My guess is that charging the 12v battery takes time, not miles.)

A misquote from Ford...
We size our batteries so that you can park at the Minneapolis airport in the middle of January. Get on a plane for a month long vacation. Come back and have it start.

 

Ford
Found
On the
Road
Dead

The mild hybrid was not a horribly bad idea. It is extra weight, but not all the weight of a full hybrid, or plug in hybrid. Much less dead weight than either.

 

Being my car came with summer tires I parked it all winter long. About once a month, I started it up and ran up for about 10 minutes. No issues.

 

Thanks for the update.
My 2025 CLE53 Alpine grey Cab had a few interesting messages displayed since taking delivery in late May, however they all disappear after turning the car off and then restarting after 5 min.
My Jaguar XKR and MB S560 has electronics but they are not over loaded like the new MBs
Cheers