48 Volt battery problem? Check in here.
 

Some owners are having a problem with their 48 V battery. The car will shut down an error code will appear on both screens. The car has to be put into neutral and towed to a dealership. It's happened to me twice.

If you have been impacted by this problem please post to this forum. Whatever type of Mercedes you drive please post. This way we can begin to get an idea of how many people are having this problem.

Is it the exception to the rule or the rule?

Car: E450 All Terrain
MY:2021
Issue: 48v Batter Failure (error on screen was actually a 12v system failure)
Mileage at Failure: <50 miles (brand new car)
Fix: New 48v battery installed; no other work mentioned on service receipt
Current Status: Working at 152 miles on the odometer

This seems to affect mainly the E-, CLS- and GLE-/GLS- Class vehicles from 2019 model year and onward for the sedans and 2020 model year for the SUVs.

As of today there don’t seem to be many reports from S-, C-, or GLA-/GLB-/GLC- Class owners.

Hmmm I guess to simply put it, basically all cars with the M256 with the 48V mild hybrid system.

I have had a CLS53 for 2 years, 18K miles and thankfully, have had zero problems but I am apprehensive about this issue occurring on the MY2022 GLE53 that is to be delivered within 2 weeks (late Nov). I will certainly post any issues here. That you for starting this thread.

I have posted on this issue in on another thread, but am joining this one to try and understand the magnitude of the problem.

My car is a 2021 E 450 All Terrain with approximately 6,700 miles, delivery taken at the end of March 2021. It would not start 5 days ago while parked in the garage and had to be flatbed towed to the dealer. (BTW....the MB Roadside assistance is great up until you need it. I waited over 11 hours for my car to be successfully extracted from the garage and hauled away.) As of today my car has been with dealer for 5 days and other than confirming it would not start due to a faulty 48v battery, I have received zero support from the dealer. I am without a car (no loaners are "available") and they have given me no information on how long my car will be out of service. I can't even get them to confirm that Mercedes has authorized a battery replacement.

Dealer insists this is an extremely rare occurrence, and that they don't stock 48v batteries because they are lithium and they don't hold a charge in storage. Based on this forum, I am having a hard time believing that this is a rare occurrence.

Other than that....crickets. Very disappointed in both Mercedes Benz and the dealer. They can do a lot better than this.

It is not rare.

https://mbworld.org/forums/cls-coupe...y-problem.html

https://mbworld.org/forums/e-class-w...ip-report.html

I feel your pain.

My 2021 E450 All Terrain wagon is on its third 48 volt battery. The first battery failed after 15 days and 196 miles. The second battery died after 30 days and 535 miles. The third and current battery is still alive and well after 5 months a little over 3,000 miles, but my confidence still hasn't been restored.

Phil, the last I remember hearing from you was that your car was being towed in to the dealer (a few weeks ago as I recall). I assume (hopefully) that you're back on the road again? What was the fix and how long did it take them to get you back up and running again?

Phil, I just re-checked and see your earlier post was just over a week ago, so I'm guessing you might not even have your car back yet. I'm curious as to what the dealer is saying/doing?

That sounds right to me. I was keeping track for awhile and the problem seemed to run across all products with the turbocharged in-line 6 with EQ Boost. However, I thought I saw a different pattern between the 2021 and pre-2021 models. With the former, it seemed some owners were able to get the car re-started, at least temporarily; whereas, the 2021 models were dead as doornails and needed to be flat-bedded into the dealer. Could that have something to do with the fact that the 2021's are belt-less? Or is that also the case with earlier models, if you know?

48 Volt Issues? Check the "Consumption" Display
 

Perhaps the "Consumption" display could show warning signs that indicate an impending problem with the 48 volt system. I suggest you should check this periodically, maybe at least once a day if you have concerns.

I'm not sure what display of battery/charging is incorporated into the latest MBUX. On my '19 CLS53 (no MBUX) this display is accessed by selecting "Vehicle" and then "Consumption". The green bars show "Charge %" which is NOT the amount of charge on the the Lithium battery. It is the percent of charging BEING APPLIED by the MGU to the batteries. I complained to MBUSA that we need a display of the charge level of the battery such as is provided to the EVs, but no such luck. Maybe with MBUX try saying "Hey, Mercedes, what is the charge level on my batteries?"

Two samples of this display are attached below. The first is typical of "normal" driving where the "Charge %", the amount of charging being supplied is 5-10% of the maximum output of the MGU over a 30 minute period (you can select 60 minutes also). The second image was taken during the long, 15 mile descent into Denver from the mountains where the charge occasionally reaches near 100%. If your system is operating normally, you should see displays like this and if you become familiar with how this display looks under various driving conditions, you might be able to detect an impending problem. Let us know if you see anything anomalous.


https://cimg9.ibsrv.net/gimg/www.mbw...da01a7e37c.jpg


https://cimg4.ibsrv.net/gimg/www.mbw...8b2266d23b.jpg

Just had a 2021 E450 with 300 miles on it display the same message. It has been trucked back to the dealership, they are bringing me a loaner car tomorrow. Am guessing this will be related to the 48 volt battery issue I have been reading about. Will let you know the outcome of their diagnosis. Still will be wary of this car now, almost 60 years of driving and only one terminal failure, now two. Disappointed in MB for selling these cars without mentioning this potential problem.

Sorry for your problem. Do you know your build date? I think everyone on this forum is trying to find a pattern to these failures, and the early theories were that there was a bad batch of batteries in late 2020 into at least Spring or Summer 2021. I'm guessing your build date is much later if you only have 300 miles on it?

Sorry you are having this problem. We feel your pain.

My car failed twice in 60 days. I received this error a second time, 1000 miles after the first failure. My car was there a week they told me that the engineering personnel determined that this is a software problem updated my software. I'm crossing my fingers that the problem has been resolved.

I have no knowledge of battery technology but it is logical that it is a software problem because it seems to me that by now battery manufacturers have their act together.

It is a shame that MB seems to not care.

I suspect MB cares, Phil. They can't be thrilled about replacing so many expensive 48 volt batteries. They're just not talking (as in issuing a recall) and I don't think it's because they haven't gotten to the bottom of the problem. These are arguably the finest automotive engineers in the world. I'm guessing they don't have an economical across-the-board fix for the problem so they're being totally reactive by updating software and replacing 48 volt batteries as needed, and the result is a lot of disgruntled MB owners.

I've reported my failures to the NHTSA as suggested by other members of this forum. The hope is that if enough owners report their battery failures as a safety issue, maybe it will encourage MB to be more proactive.

I should have added that I don't know what NHTSA considers a safety issue. Fortunately, both of my failures have occurred while the vehicle was at home, but I suppose it could have happened anywhere. Other members have reported failures while one the road. One person mentioned that the problem occurred while in a high speed lane on the highway and he felt fortunate to be able to get the car to the shoulder. It concerned me enough that I changed my plans for a road trip and opted to fly instead.

MB Issue
 

I will let you know, probably need the data plate on the car. If there is a way to look it up by VIN it is: W1KZF5KB5MB002067. Thanks for your interest. Just for information, this is my second Mercedes, made the mistake of buying a 190E back in the '80's, second worse car I ever owned. Looks like I have made another mistake.

Indeed. I’ve got that feeling of dread that I have made a costly mistake. It is tough to swallow spending 80k+ on a road trip car and be afraid to road trip it.

Add in the rattle/squeak interior and I wish I had just gone with something else at this point.

It's on the jamb of the driver's side door but since your car has been hauled off that probably doesn't help much. I don't know how to figure it out from the VIN, sorry.

I wouldn't count the car out quite yet. I know this sounds like "Other than that, Mrs. Lincoln, how did you enjoy the play?", but I have the E450 wagon and, aside from that little old battery thing (wink wink), I actually love the car. I love the powertrain and I love the tech. It's a great ride. However, like Phil, who commented above, I also had two failures, the first one at under 200 miles and the second at under 1,000. In my case they actually replaced the 48 volt twice and updated the software, and I'm still going strong 3,000 miles later and enjoying every minute of it. One problem, of course, is that it shatters your confidence in the reliability of the car, so you keep waiting for the other shoe to drop. And of course the overriding problem is MB's apparent refusal to address issue with a recall or at least a statement that they've identified the problem. Instead, we're all left to get our information on a case by case basis from the various dealers (and the dealer responses aren't always consistent), and from the exchange of information on this forum.

The good news is that, other than Phil and me (I think we were both 3/21 build dates), I don't think there have been any other reports of repeated failures once the 48 volt has been replaced and the software updated. So, hopefully, you'll be "one and done" have and have miles of good driving ahead of you. Fingers crossed.

2021 AMG GLE 53 with 6000 Miles, got the car in August. This morning the car wouldn’t start with a battery message on the screen. Stated that the 12 volt battery was affected. The dealer is sending me a loaner and will pick mine up for repairs. This sucks!

I was stressed but in the end we are lucky to be in a position where we can buy an expensive car. I hope they fix you the first time. In two weeks you won't remember this,

Well said, Phil. Worrying about. the performance of of an $80K+ luxury car is a first world problem, all things considered. This should be the worst of our problems.

Had the vehicle been driven recently or was it parked for some time without a trickle charger? We need to keep these 12 volt batteries charged with a home charger. If the 12 volt battery is not charged I don't believe the 48 volt battery will be charged.

slk55, That is a great question! Is something draining the battery??? The new app is always sending me messages. I wonder it that app is draining the battery? (ps: your name dates you so does mine Smile)