48V Battery Management System Software update campaing
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Junior Member
Joined: Jan 2025
Posts: 21
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From: Memphis, TN
GLS450
48V Battery Management System Software update campaing
Just received notice of an emissions service campaign for the 48V battery system. Apparently MB needs to reprogram the 48V battery management system since it might or might not trigger the MIL (check engine) lamp. Campaign covers 2019-2022 vehicles. Has anyone had this done yet or experienced the stated symptoms?
For reference, campaign number is 2025050001 (CA DMV #250724).
For reference, campaign number is 2025050001 (CA DMV #250724).
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2020 GLS450 (wife) / 2024 Ford Bronco (mine) / 2014 VW Tiquan (son)
I’ve never experienced that. Only one time did I have a warning for the 48v battery shortly after we bought it (maybe 500 miles on the car then). Message went away and has never returned (5 years and 85k miles later).
My advice? When it comes to MB…if it ain’t broke, don’t fix it. Because I promise you, it will be broken then. Just leave it alone. If you get the light, then fix it. But until then, don’t worry about it. At this point, if it hasn’t happened, then I doubt it ever will, unless if you let MB fiddle with it.
My advice? When it comes to MB…if it ain’t broke, don’t fix it. Because I promise you, it will be broken then. Just leave it alone. If you get the light, then fix it. But until then, don’t worry about it. At this point, if it hasn’t happened, then I doubt it ever will, unless if you let MB fiddle with it.
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Don't know if there's a recall, or just a campaign.
You can check your VIN at MB to see if your car has a recall.
https://www.mbusa.com/en/recall
You can check your VIN at MB to see if your car has a recall.
https://www.mbusa.com/en/recall
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2021 GLS580 | 2011 ML350 BlueTec | 2009 Pontiac G8 GXP
BMS (Battery Management System) update. It likely reduces the sensitivity of faults to prevent issues. Based on my experience with Lithium batteries they were way conservative with shutting down the 48v components due to a perceived fault. Problem is this shuts down critical systems, most notably the engine coolant pump, along with it which will quickly overheat the engine. Another case where saving .02 MPG by using an electric water pump instead of a mechanical one turns a small failure into a major failure.
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Joined: Oct 2009
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
BMS (Battery Management System) update. It likely reduces the sensitivity of faults to prevent issues. Based on my experience with Lithium batteries they were way conservative with shutting down the 48v components due to a perceived fault. Problem is this shuts down critical systems, most notably the engine coolant pump, along with it which will quickly overheat the engine. Another case where saving .02 MPG by using an electric water pump instead of a mechanical one turns a small failure into a major failure.
The other reason for the electric water pump is the elimination of pulleys altogether, which shortens the engine.
And the ability to continue to circulate coolant after the engine is off. I think that also includes the turbo, but I haven't verified that.
My most recent software update keeps the circulation on longer than before.
Last edited by mikapen; Jul 30, 2025 at 11:39 AM.
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Senior Member
Joined: Dec 2009
Posts: 287
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From: McLean, VA
2011 Audi A4, 2014 E63S Wagon, 2020 GLS 580
Just received notice of an emissions service campaign for the 48V battery system. Apparently MB needs to reprogram the 48V battery management system since it might or might not trigger the MIL (check engine) lamp. Campaign covers 2019-2022 vehicles. Has anyone had this done yet or experienced the stated symptoms?
For reference, campaign number is 2025050001 (CA DMV #250724).
For reference, campaign number is 2025050001 (CA DMV #250724).
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Thread Starter
Junior Member
Joined: Jan 2025
Posts: 21
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From: Memphis, TN
GLS450
I'm going to schedule my Service B and some CPO warranty work at the same time. I don't trust the "30 minutes" estimate and want to get the most of my dealer visit!
Super Member
Joined: Feb 2017
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GL350 Bluetec and GLS580
FYI, last week the dealer told me there is a "bug" in the BMS update so they are waiting for MBUSA to provide a new updated software. Meanwhile I've gotten the BMS update 2x since but never before my dealer visit.
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Joined: Sep 2019
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From: U.S.
Current/Last 5-years:GLS;G70;Alpina B8;X7;Accord. Sold:X7,TeslaS;S560;S550,X5;530e;L.Navigator;LS460
Owning a Mbenz and other german brands at the same time, makes the benz feels so outdated, technologically poor, disappointing on the user experience side. This should be an OTA recall.. not a dealer visit, yet even dealers don’t have the right update. Mbenz is just relying on blind customers who never experienced anything but their poor tech and all their boring lineup. Am glad the GLS at least is still looking as an exciting vehicle inside and outside.
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Joined: Sep 2009
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From: New York
2024 GLS 580
I got a message about an update needed about rough engine or something. I checked recalls on the recall website and nothing was noted. I finally brought it in and there were a few recalls noted by the dealer. All were done overnight and I never experienced anything that I recall. Just wanted to note about the recall discrepancy. 2024 GLS 580.
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Joined: Mar 2017
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GLS450 & Range Rover Sport
2 weeks back, took my 2020 GLS450 for NY State Inspection (also had the check engine light on), but instead they just did 60K service (filters along w/ brake fluid/transmission fluid changes), and also the above S/W updates - Control Unit Software and recall software update - 48V Battery Management System. They didn’t perform NY state inspection as check engine light was on and said that will go off once I drive 150-200 miles and that I could bring back for inspection.
Problems noticed -
Problems noticed -
- Since the 48V battery mgmt s/w update, we’ve noticed that the engine Fan continues to run for about 20 plus minutes after I turn off the vehicle. This behavior didn’t occur before the update. And we noticed this while only parked in our Garage. I checked w/ another dealer and he said it’s what the battery mgmt s/w update was supposed to do and since it’s enclosed space this behavior happens and it’s normal behavior.
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2020 GLS450 (wife) / 2024 Ford Bronco (mine) / 2014 VW Tiquan (son)
2 weeks back, took my 2020 GLS450 for NY State Inspection (also had the check engine light on), but instead they just did 60K service (filters along w/ brake fluid/transmission fluid changes), and also the above S/W updates - Control Unit Software and recall software update - 48V Battery Management System. They didn’t perform NY state inspection as check engine light was on and said that will go off once I drive 150-200 miles and that I could bring back for inspection.
Problems noticed -
Problems noticed -
- Since the 48V battery mgmt s/w update, we’ve noticed that the engine Fan continues to run for about 20 plus minutes after I turn off the vehicle. This behavior didn’t occur before the update. And we noticed this while only parked in our Garage. I checked w/ another dealer and he said it’s what the battery mgmt s/w update was supposed to do and since it’s enclosed space this behavior happens and it’s normal behavior.
What's that you say? You took your otherwise perfectly running GLS to the dealership for a battery management system update, and now they tell you it needs a new $2,500 battery? Kind've begs the question of what was so bad with the previous battery management system program... Please tell me you see the BS connection here.
Look up an indi shop in your area that works on MB. Take the car there, slip the guy a $50 to scan the car for the code, verify the code's meaning, and if battery related, have the code deleted to see if it comes back on. I would do this before I trusted what the dealership tells you. I would also request the dealership to reinstall the previous battery management program to verify the issue here isn't a bad computer program update instead of a bad battery.
Only battery issues I've seen on here were in the early models that had defective batteries from the start, leaving them stranded. Either the battery was bad, or the ground wire was loose. I've not seen anything about needing a new battery because it was worn out. Our 2020 (knock on wood) is just fine at 92k miles, garaged. Never serviced at the dealership since day 1. Only dealership visits were for a squeaking driver's window (still squeaks), bad MBTex seat covers on the front seats. Otherwise, it doesn't go anywhere near a MB dealership.
Last edited by nc211; Jan 17, 2026 at 08:51 AM.
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
What's that you say? You took your otherwise perfectly running GLS to the dealership for a battery management system update, and now they tell you it needs a new $2,500 battery? Kind've begs the question of what was so bad with the previous battery management system program... Please tell me you see the BS connection here.
.......
.......
The software would have downloaded eventually, as it did on mine.
The dealer updated it while it was in the shop as a courtesy, and as part of troubleshooting. An Independent shop can't install software, or even know if one is scheduled.
I doubt that it can be uninstalled, but why would you want to do that?
These are the kind of things that independent shops really can't address adequately, except by parts swapping. Which is ultimately futile and expensive.
So this is a good example of why a good relationship with a dealership can be valuable.
Last edited by mikapen; Jan 17, 2026 at 03:01 PM.
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2020 GLS450 (wife) / 2024 Ford Bronco (mine) / 2014 VW Tiquan (son)
He went in because his warning light was on.
The dealer updated the software while it was in the shop as a courtesy, and as part of troubleshooting. An Independent shop can't install software.
I doubt that it can be uninstalled, but why would you want to do that?
These are the kind of things that independent shops really can't address adequately, except by parts swapping. Which is ultimately futile and expensive.
So this is a good example of why a good relationship with a dealership can be valuable.
The dealer updated the software while it was in the shop as a courtesy, and as part of troubleshooting. An Independent shop can't install software.
I doubt that it can be uninstalled, but why would you want to do that?
These are the kind of things that independent shops really can't address adequately, except by parts swapping. Which is ultimately futile and expensive.
So this is a good example of why a good relationship with a dealership can be valuable.
Either way, I would have the code pulled to verify and reset the code to see if it comes back on.
At around 1,500 miles on ours, I got the battery error message too coming out of the store. Drove it home like that, and the next time I started it, the code was gone and has not come back ever since (5+ years ago). I'd at least reset the error to see if it comes back on before I spent the thousands on a new battery (assuming the car is operating normally in general).
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
[QUOTE=nc211;9254917]Opps, my bad I missed that part! Thought he had the software updated as part of the 60k service and then the check engine light came on. But still, if the light was on during the 60k service, wouldn't they have been able to determine the battery was bad in general? Or was the software update meant to cure that? Either way, I would have the code pulled to verify and reset the code to see if it comes back on. At around 1,500 miles on ours, I got the battery error message too coming out of the store. Drove it home like that, and the next time I started it, the code was gone and has not come back ever since (5+ years ago). I'd at least reset the error to see if it comes back on before I spent the thousands on a new battery (assuming the car is operating normally in general). It sounds like the shop followed your troubleshooting procedure. Regarding your battery warning, it's "normal" if you only short-trip. It takes almost an hour of highway driving to recharge. The Mercedes me app will show "partially discharged" before the dash warning appears. (I think.)
I put a maintainer (CTEK for me) on the car if it's going to sit for more than a week, since there are so many things that consume electricity in the background.
Such as listening for and downloading software updates.
I put a maintainer (CTEK for me) on the car if it's going to sit for more than a week, since there are so many things that consume electricity in the background.
Such as listening for and downloading software updates.
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Joined: Jan 2023
Posts: 27
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2020 GLS450
2 weeks back, took my 2020 GLS450 for NY State Inspection (also had the check engine light on), but instead they just did 60K service (filters along w/ brake fluid/transmission fluid changes), and also the above S/W updates - Control Unit Software and recall software update - 48V Battery Management System. They didn’t perform NY state inspection as check engine light was on and said that will go off once I drive 150-200 miles and that I could bring back for inspection.
Problems noticed -
Problems noticed -
- Since the 48V battery mgmt s/w update, we’ve noticed that the engine Fan continues to run for about 20 plus minutes after I turn off the vehicle. This behavior didn’t occur before the update. And we noticed this while only parked in our Garage. I checked w/ another dealer and he said it’s what the battery mgmt s/w update was supposed to do and since it’s enclosed space this behavior happens and it’s normal behavior.
Just got these 2 performed:
- Campaign# 2025050001: Perform Software Update – 48V Battery Management System
- Campaign# 2025100006 : Update Engine Control Unit Software
Once parked in the garage, after 20min long drive, radiator fan kept running for at least 10-15 minutes while car was shut.
This has never happened before. I assume it is due to the 48V system software update that may be related to battery cooling.
No idea what the second ECU update does.
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2020 GLS450 (wife) / 2024 Ford Bronco (mine) / 2014 VW Tiquan (son)
Interesting.... I just checked the MB recall site, and showing only two for mine, one I've know about for a long time.
(1) hard shifts down from 7 to 6th gear.
(2) potential loose ground bolt for the 48v battery.
That's all I see for our 2020.. The battery works fine, and the hard shifts aren't 7-6, but 4-3-2-1...
(1) hard shifts down from 7 to 6th gear.
(2) potential loose ground bolt for the 48v battery.
That's all I see for our 2020.. The battery works fine, and the hard shifts aren't 7-6, but 4-3-2-1...
