Mercedes Benz 48V Battery Problems

By Brian Jones | Updated on

By Brian Jones | Updated on

Lemberg Law is investigating complaints regarding battery problems for various Mercedes-Benz vehicles including GLE, GLS, CLS, and E-Class models. Vehicle owners are reporting to the NHTSA their batteries are dying after owning the car for a short period of time. 

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Is There a Problem with the 48V Battery in Mercedes-Benz Vehicles?

Yes, there are major problems with the 48V battery in a wide range of Mercedes-Benz vehicles. National Highway Traffic Safety Administration (NHTSA) has logged numerous complaints from vehicle owners regarding a battery issue in several 2020 and 2021 models. These include the 2020 GLE and GLS-Class, the 2020 CLS, and the 2021 GLE, E-, and GLS-Class models.

More specifically, the battery fails causing the vehicle to not start, inconveniencing owners. This usually follows a warning that says: coolant too hot, shut engine off, with a red check engine light coming on. The malfunction also leads to other problems including overheating and air-conditioning problems.

Mercedes-Benz 48V Battery TSB

Mercedes-Benz issued a technical service bulletin (TSB) for this problem, NHTSA ID Number: 10189404, on February 19, 2021. The TSB lists the possible causes along with remedies for each.

Of the five possible listed causes, two are software-related, one is hardware-related, one is a cooling issue and the last is a false-positive detection error, which causes the “48V battery to disconnect itself.” It also recommends the replacement of 48V batteries in several Mercedes-Benz models.

Depending on the cause, the vehicle may:

  • Not start
  • Display a yellow or red instrument cluster notification regarding the 48V battery
  • Trigger “limp home mode” as well as overheating, loss of acceleration, or A/C not working correctly

The TSB was reissued, with additions, on December 1, 2021, with the NHTSA ID Number: 10206063. But it seems that these TSBs have not solved the problem.

An even more recent TSB issued on March 31, 2022, states that the “battery test does not match the current state of the battery.” According to the TSB, NHTSA ID Number 10209877, “A discharged battery does not necessarily need to be replaced. A discharged battery may be recovered with no permanent damage.” However, if dealers are unable to diagnose and fix the problem, Mercedes-Benz says they must create a product technical support system (PTSS) case.

All three of these TSBs are filed in the manufacturer’s communications for the Mercedes-Benz 2020 CLS, 2020 and 2021 GLE-Class, and 2021 E-Class on the NHTSA website. The original February 2021 TSB is listed in manufacturer communications about the 2020 GLS but not the other two. And there are none of the 3 TSBs on file with NHTSA for the 2021 GLS, even though this model clearly has the same problems.

What Battery Problems are Benz 48V Battery Owners Experiencing?

We have identified numerous complaints about how 48V batteries in GLS, CLS, and GLE- and E-Class Mercedes-Benz SUVs die. In many instances, the vehicle simply doesn’t start. In other cases, owners experience a 48V battery warning light on the dashboard or in more severe cases, overheating or loss of acceleration while driving.

Here are just a few of the complaints on file with NHTSA:

2020 Mercedes-Benz GLE Battery Problems

An owner from North Carolina identifies the battery problems as a safety issue.

“Driving down the highway at 70, a 48V battery malfunction warning goes off along with a yellow check engine light. A few seconds later a ‘coolant’ error message pops up and a red check engine light comes on. Car loses power completely and I’m unable to accelerate at all. Call flashes a message of ‘Pull over and turn the engine off. Fortunately no-one was behind me and I was able to coast safely to the side of the highway before the car stalled completely.”

This owner discovered via blog posts that other 2020 GLE owners had the same safety issue. But there was no recall by Mercedes-Benz and there was not a resolution for the issue.

“This is an incredibly dangerous issue to lose all power and control of the vehicle’s speed. I’m lucky no-one was on the road near me when this happened, otherwise an accident almost surely would have occurred. Mercedes should be forced to address this safety issue immediately.”

2021 Mercedes-Benz GLE Battery Problems

An Illinois owner complains: “It is incredibly distressing to have experienced an issue that is widely reported in this database and online forums, and remains unaddressed by MBUSA. It also seems to be an entirely preventable issue that can be fixed via a software update. The issue relates to a malfunction of the 48V battery that made the vehicle inoperable. It happened in the midst of winter and we would have been in a dire position if our family did not come to the rescue to pick us up. The vehicle had to be towed to a dealership.”

An owner from Massachusetts states: “While driving at various speeds the vehicle loses motive power. The 48V battery malfunction and coolant hot turn-off vehicle message were displayed on the instrument panel. The battery indicator warning light was illuminated. The vehicle was taken to the local dealer and diagnosed with a software issue. The contact was informed that the software needed to be updated. The vehicle was repaired however, the failure recurred. The manufacturer was not notified of the failure. The approximate failure mileage was 3,000.”

A New Jersey owner whose GLE53 had less than 5,000 miles on the clock complained that it would not start. “The car threw an error stating 12V battery malfunction. (Impacted the 48V battery) This essentially disables the vehicle completely.”

An owner from Maine states: “There are numerous reports of the 48V battery failing on multiple Mercedes models using the 6-cylinder with ISG engine. Mercedes should do a recall to replace all 48V batteries as this problem makes the car unreliable and unsafe to use as sometimes the 48V battery system fails while driving.”

2020 Mercedes-Benz CLS Battery Problems

An Arizona owner labels the CLS “dangerous.”

“The 2020 Mercedes CLS has a known defect in their 48V system that turns the engine off in locations with high heat zones. I was told by the Mercedes service department this has been occurring in Arizona, New Mexico, Florida, Nevada, and Saudi Arabia. It’s a known issue that they are unable to fix currently.”

2020 Mercedes-Benz GLS Battery Problems

An Illinois owner describes the results of the battery problem as terrifying. After displaying a 48V battery malfunction, “the car warned me not to drive the vehicle under any circumstance. This was while driving at 55 mph on a country road. The dealer I bought the car from had 3 other cars brought in for the same issue. The dealer my car was towed to said they just had one with the same issue come in.

“Based on my reading, this is a serious issue and it appears that changing the battery does not correct the issue. I was transporting my entire family at the time. The thought of not being able to break when traveling at high speeds is terrifying. Seems to be a widespread issue on the newer cars. Mine is only a year old.”

2021 Mercedes-Benz GLS Battery Problems

An owner from Florida states: “The car would not start and could not be jumped. I’m told the 48V battery has to be replaced. I have seen on the internet numerous people have the same problem and that a large batch of these 48V batteries are the problem. Error message displays stop the vehicle and more details advise battery is malfunctioning and do not continue driving.”

2021 Mercedes-Benz E-Class Battery Problems

An owner from Ohio complained that the 48V battery failed twice. “The 48 volt battery on this mild hybrid vehicle failed and the car was unable to be started on May 3, 2021, with 196 miles on the odometer, a mere 15 days after delivery. It had to be taken by flatbed to the dealer where ultimately the 48 volt battery was replaced. Then again on June 5, 2021, the car was again unable to be started, with a mere 735 miles on the odometer. Again, the car had to be taken by flatbed to the dealer, where ultimately the 48 volt battery was replaced a second time.

“While both failures, fortunately, happened while the vehicle was at home, this could have happened on the highway, in the middle of nowhere in bad weather conditions, or anywhere. I have had to cancel a cross-country drive for fear that, once again, the 48 volt battery will fail, leaving us stranded anywhere or, worse yet, in the middle of a highway.”

An owner from an unknown location is also afraid the problem will recur. “48 Volt battery failed after three months and just 3,400 miles. I understand this is a recurring problem with Mercedes. Car had to be towed as the vehicle was totally inoperable due to battery malfunction. It took more than three weeks for Mercedes to provide a replacement battery. From what I have read, there is a strong likelihood that the battery will fail again.”

What should you do if your Mercedes-Benz is experiencing a 48V battery issue?

It is possible that your GLS, CLS, E-, or GLE-Class SUV is a lemon. Allow our team to work on your lemon case at no cost to you. The law requires Mercedes-Benz to pay the legal fees for your claim.

Brian Jones

About the Author:

Brian Jones spent more than 20 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

See more posts from Brian Jones
2 COMMENTS
  • Freightened +

    2021 GLS 450 Mercedes Benz within several days of purchasing in late Fall 2021, while in motion at 65MPH or more, the vehicle suddenly flashed all kinds of malfunction warnings (the entire dashboard was lit up w every system “warning”) including 48V battery code, within seconds the car shut down while driving on the highway, no power steering, no brakes, no anything – nearly lost our lives as we maneuvered out of the fast line in the dark during rush hour traffic to “coast” to a stop. This is a very dangerous and serious life-threatening problem that has been wontonly ignored by the manufacturer and the NHTSA has taken complaints but has not fully investigated the GLS. The dealership service centers did nothing, there is no remedy as we had it in the shop for the past 12 months we only drove it for 3 out of the past 12 trailing months on and off as it would repeat the above, nearly killing us multiple times, or would be dead in parking lots and driveways without any solution. Even the two truck companies declined to deal with it citing the risk of fire, and danger to tow. This is a KNOWN ISSUE that Mercedes Benz has not found a solution to remedy. One can only imagine that there have been injuries and deadly accidents where there is nobody to tell what happened to them, since when this issue happens there is NO RECORD of it happening by the on board system. Dealership continues to say they can’t find anything wrong and admits there is no viable fix, even replacing the 48V battery DOES NOT solve the problem, they all have the potential to have this deadly problem.

  • Paul

    2021 gle 63s vehicle inoperable, showing warning for battery, stop vehicle see operator’s manual.

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