12V BATTERY ISSUES WITH GLC 4MATIC AMG LINE COUPE 2022

[Rippedoff]

Hi,

I have read many posts regarding the issues with the Mercedes 12V battery, my car is less than 12 months old, I even brought my service forward to try and get the issue resolved. In the first 8 months I didn't have any issues with my car. But I started to get emails and the 12v battery was showing critical on the Mercedes Me App. I know a lot of people don't like the app, but I find it a good indicator and more often than not when I get in the car after the notification on the app there is a warning on the dash.

My car has been in the dealership every week for the past 3 weeks, today was the last straw I got it out of the dealership with a fully charged battery, but when I got home 3 miles later within a couple of hours I received an email stating that the 12V battery was critical, surely this cant be right.

I am convinced there is something wrong with the battery but the dealership cant find anything wrong with the diagnostic's, I know I don't drive it longs runs every day, but at weekends it is driven on the motorway for hours. In fact I am taking it out on long runs when I don't need to go anywhere, using petrol that I don't really need to use, to try and resolve the issue, I fear that one day it wont start.

Is any one else having the same issues and how are you getting on having the issue resolved.

Many thanks in advance.

 

[Blobcat]

Test the battery yourself before starting the car - if it’s >12.4v it’s fine.
Is the engine turning over quickly and starting first turn? If so the issue is with the app being overly cautious

 

[ajlsl600]

As above. When resolved turn app off.

 

[malcolm E53 AMG]

Welcome,
Sorry to hear this!
Probably a good time to buy a multimeter to check the state of the battery and the alternator charging rate when the engine is running.
There are plenty of ‘how to’ videos on YouTube to help you do this it’s safe and simple to do

 

[Srdl]

Certainly not normal. This is a new car, under warranty, so it’s up to Mercedes to sort it. I would suggest two options to try:
1) take it to them, demand a quality courtesy car, and tell them to keep it until they’ve sorted it.
2) phone Mercedes Customers Services, register a complaint and ask them to put pressure on the dealer.

Good luck!

 

[Headhurts]

I have a 2021 GLC300 that on purchase had only completed 2300 miles, to get the spec I required entailed me travelling a decent distance around a 5 hour drive back to Norfolk.

I kept getting the same warnings as you so I charged the battery a couple of times with a CTEK MXS 5 charger but I was still getting the warnings.

I then decided to set charger to AGM and recondition, this took around a day and a half, that was 6 months ago and my car has been perfect since.

NOW A WARNING……

Despite the booklet showing this as an option a forum member told me this can damage the battery and an email to CTEK elicited the same response so I’m not suggesting you follow my route and as mine like yours is still under warranty if I’d known I would have left it to the dealership to sort out.

I have no technical knowledge I’m just relaying what happened in my circumstances, it seems as if the battery can read ok but due to the seemingly high demand on batteries these cars have that if there is the slightest deficiency with the battery they can cause errors in the car.

Robin

 

[Uncle Benz]

It won’t let you down with regards to starting the car. However, cars that aren’t used every day will quickly suffer battery degradation that stops the stop/start working and begins to flag battery warning both on the app and on the dashboard when you unlock the car and before you start the engine. Occasionally a very long run can revive the battery but in my experience, more often than not, the battery has sunk below the levels the software is happy with. In this instance a new one is the only cure. If you don’t plan to use the car every day though, you will soon be back in the same place

 

[rf065]

Do you know if your car has a capacitor behind the glove box instead of an auxilliary battery? Does the stop/start work?
My C Class used to give me Mercedes Me warnings that the battery was critical, even during a 2000 mile trip to Spain/France and back driving hundreds of miles every day. Turns out the capacitor was at fault and replaced under warranty, problem solved.
If your stop/start works, then your battery is OK, I look at the stop/start system as a battery condition indicator, as the slightest battery problem will stop it working.

 

[Rippedoff]

Thanks everyone I appreciate your input, after a fight with the Dealership and an email to Mercedes CEO, a new battery is being installed tomorrow. Lives have changed with covid and not everyone uses their car daily, had I known that the battery would have issues I would have steered away from this car, but Mercedes have said that we would get this issue with any new car. The joys of technology.

 

[Srdl]

Thanks everyone I appreciate your input, after a fight with the Dealership and an email to Mercedes CEO, a new battery is being installed tomorrow. Lives have changed with covid and not everyone uses their car daily, had I known that the battery would have issues I would have steered away from this car, but Mercedes have said that we would get this issue with any new car. The joys of technology.

It shouldn’t be a problem. When my wife was alive, mine was used once a week, if that, because her MIni was our daily. I didn’t have any battery problems. Hopefully, the new battery will solve the problem.

And, well done, good result!

 

[Timeandleisure]

Case 2 of similar battery issues on this thread at least)....

I also experienced a couple of non-starts early Feb (about 4 months into my ownership of the car), on initial start-up. This did resolve however, after a couple of further attempts at starting the car. I was driving it daily at reasonable mileages and I think I may have posted about it before...

It was at the garage for a couple of weeks, where the battery had reached critical but I was reassured this was because they had disconnected the battery and that it was fine. When delivered the battery did show up as charged but the garage is only 7 or so miles away.

This happened again yesterday, along with a couple of error messages related to the ESP: 'Inoperative See Owner's Manual' and Active Brake Assist Functions limited See Owner's Manual.

So I am waiting on Mercedes Assist. and as an aside, I was happy to be given a choice of regular assistance or a Mercedes Specialist which I though were becoming rarer than hens' teeth.

Curious to know if the OP had a software update shortly before the issues started occurring? I would also love to know what was said exactly to Merc CEO to get the issue resolved?

Any safety critical devices requiring batteries for operation, need to adhere to regulations and standards, where (although not necessarily disclosed), risk analyses to establish acceptability of risk would need a quantification of min battery life for their assessments.

In my opinion, I don't think battery life of less than 24 months is acceptable.

It was due its service B on Monday as well...

 

[Timeandleisure]

Verdict: Faulty wiring from Relay N to its associates... Thankfully not a mainly a battery issue since it was at 11.something V but could also explain why the engine cut out mid drive with the previous owner.

To be towed.... laughing stock for the neigbours again....

 

[Flyinspanner]

11.something is too low.

at 11.9v your battery is only at 40%.

try getting a reading as you crank it.

 

[Timeandleisure]

11.something is too low.

at 11.9v your battery is only at 40%.

try getting a reading as you crank it.

Yes it is, so I will be taking this up with the garage at the same time... Merc assist have gone now and I don't have the means where I am at the moment.

Thank you and I really I appreciate your helpful advice which I will use to help bolster the ammo...

 

[Timeandleisure]

I couldn't find a thread similar enough to my question and am adding it to the unfolding story, if that's ok?

How would you recover this? The chap trying to recover the car was a really nice and helpful chap, but didn't want to risk it in the end in case my rear bumper got damaged in the process. The car moves through gears via an arm on the steering wheel and with the non-start situation it wouldn't get out of park. The steering was too heavy and wouldn't move. This in addition to the rear being towards the road and the drive on the start of a bend, the truck couldn't make a straight line nor would the wheel turn to move the car. He wouldn't have given it a go if the axle wasn't so far forward.

Looking into a grabber.... but is there another way?

 

[Blobcat]

I couldn't find a thread similar enough to my question and am adding it to the unfolding story, if that's ok?

How would you recover this? The chap trying to recover the car was a really nice and helpful chap, but didn't want to risk it in the end in case my rear bumper got damaged in the process. The car moves through gears via an arm on the steering wheel and with the non-start situation it wouldn't get out of park. The steering was too heavy and wouldn't move. This in addition to the rear being towards the road and the drive on the start of a bend, the truck couldn't make a straight line nor would the wheel turn to move the car. He wouldn't have given it a go if the axle wasn't so far forward.

Looking into a grabber.... but is there another way?

Recovery can be done with wheel skates, they fit around the tyre and lift it up then the casters mean it can be pushed around.

 

[Timeandleisure]

Thank you. I can't remember if he mentioned them and eliminated that idea because he thought he couldn't position the truck... most likely RAC don't have these, as he mentioned they would need to get a contractor out...

Recovery can be done with wheel skates, they fit around the tyre and lift it up then the casters mean it can be pushed aroun

 

[Timeandleisure]

I don't know why I didn't remember to mention this at the time... Since the Merc Specialist had managed to start the car with by substituing the relay with some wire concotion, he could have towed it, had he had a tow truck... So perhaps the merc specialist needs to come back only with a flatbed this time or there fancy all wheels up fancy recovery system... Wish I had engaged brain... Still waiting on whether they are going to attempt to come out tonight or not....

 

[Timeandleisure]

And so the saga continues..... RAC has maintained a steady radio silence all day whilst on my third call to Mobilo to ascertain status, received an incoming call with the caller asking if I had any high-ups! Turns out it was RAC contracts calling third parties on the hunt for the wheel skates that Blobcat so expertly mentioned above... only he managed to find my phone number instead... He said he had only just been given the task.! Incredible given how the tow had called it in two and a half hours ago..

Still refusing to take off my coat I gave mobilio one last try a few minutes ago... looks like I may need to get my hire car before they pick up mine as it may not get recovered before Monday.... To be fair he did apologise but really......this is agonising...

Still onwards and upwards....

 

[Rippedoff]

Well my Saga continues, picked the car up on Friday, new battery installed, but only partially charged, I asked about this and they stated that it would charge whilst driving. Saturday evening there was a Mercedes Me email telling me that my 12v battery was critical and the dashboard stated the same.

Had a busy weekend so really not been anywhere but tomorrow, I am doing a 2.5 hours round trip so here's hoping, failing that I am going to have the alternator checked.

Any other suggestions? bearing in mind I am not a man and my knowledge is very limited.