[hallra]

Hello,

I have a GLC that I purchased in Mar 2016.

For the last 3-4 months, I have been consistently getting warning messages on the dash, in the phone app and through email that the battery charge is critical and it requires charging.

No matter how far I drive, sometime after I park the car, i will receive these warning messages.

This Saturday I drove the car around for 3 hrs, afterwards i checked the battery with a multimeter, it showed 12.06v, I then checked it again the next day, 20hrs later it showed 11.9v.

Today the car is in the Mercedes garage for a 2nd time to check the battery, I just received a call from the workshop to say all fine, nothing wrong with the battery... It just needs charging... The issue is your driving style... Upon questioning I am told the diagnostic equipment reports no errors.... After more questioning I am told that the battery has indeed changed characteristics as it is getting older, but there are no errors with diagnostic equipment, etc,etc, after more discussion I've asked for the service manager to call me... Alas I know what will happen, Mercedes will claim no issue and will not fix what ever is causing the problem, be it the battery, the alternator or something draining the battery.

Now my point is, I have not changed my driver style for the whole period of the GLC ownership, Mercedes however blame my driving style. However my driving style was perfectly fine for 2 yrs without issue. Therefore logic dictates that the charging characteristics are not sufficient after 2yrs of aging components to charge the battery enough to support my driving style.

In my mind Mercedes should be replacing parts to allow the charging characteristics to support my style of driving.

How do I get Mercedes to do something about this problem?



Regards

Richard.

 

[Caysen]

Sounds like blaming the issue on your driving characteristics is a cop out. Surely there must be some sort of issue with whatever is monitoring your battery levels, and its not reading its status correctly. If they cant identify anything through diagnostics though, I don't know what your next step could be.

 

[Citizen613]

I have seen other posts where folk have had Battery issues , somewhat earlier than you would expect in the life of a car battery. In most occasions the dealer replaced the battery. Which may or may not have been the issue!!.

However a couple of posts, the dealer service department dug a bit deeper and found some 'high resistance cable' problem with the connection to the battery. On the 'earth' side I think. Not sure if this is the main battery lead to the vehicle body or part of the sensor arrangement.

Maybe discuss with the service dept to look at the connection leads to the battery.

 

[Grego]

We have had the same issue with my wife’s 2016 250d GLC for over 12 months. Even after 1 hour plus drives to charge the battery up the same error would reappear on the dash after a week. So in the end mercedes charged me £100 diagnostic check which confirmed that everything was fine but required a new battery at nearly £450. I obviously refused and went to Halfords and paid £150 for a new Varta battery - no issues!
It amazes me how much the dealership is able to rip people off!!!

 

[justjuni]

Hello,

I have a GLC that I purchased in Mar 2016.

For the last 3-4 months, I have been consistently getting warning messages on the dash, in the phone app and through email that the battery charge is critical and it requires charging.

No matter how far I drive, sometime after I park the car, i will receive these warning messages.

This Saturday I drove the car around for 3 hrs, afterwards i checked the battery with a multimeter, it showed 12.06v, I then checked it again the next day, 20hrs later it showed 11.9v.

Today the car is in the Mercedes garage for a 2nd time to check the battery, I just received a call from the workshop to say all fine, nothing wrong with the battery... It just needs charging... The issue is your driving style... Upon questioning I am told the diagnostic equipment reports no errors.... After more questioning I am told that the battery has indeed changed characteristics as it is getting older, but there are no errors with diagnostic equipment, etc,etc, after more discussion I've asked for the service manager to call me... Alas I know what will happen, Mercedes will claim no issue and will not fix what ever is causing the problem, be it the battery, the alternator or something draining the battery.

Now my point is, I have not changed my driver style for the whole period of the GLC ownership, Mercedes however blame my driving style. However my driving style was perfectly fine for 2 yrs without issue. Therefore logic dictates that the charging characteristics are not sufficient after 2yrs of aging components to charge the battery enough to support my driving style.

In my mind Mercedes should be replacing parts to allow the charging characteristics to support my style of driving.

How do I get Mercedes to do something about this problem?



Regards

Richard.

Hi Eric, were you able to resolve your problem? I’m having a similar issue, which is indicative of a wiring/connectivity issue as the battery itself is charged and in good condition. I’m waiting to bring to dealer but wanted to know if you have any info first. Thank you

 

[JoeND]

Wondering if anyone has an update to this or more information. I have a 2018 GLC300. Last year got the noted critical battery warning light. Car was three years old and battery was indeed drained, so thought it must just be time for a new battery. However this week, with just a one-year old battery, the warning light is back. Last year, prior to replacing, I did check the alternator (Full disclosure: I'm not a mechanic, but YouTube made the task easy enough) and from my non-educated-youtube-trained evaluation, that seemed to be working OK. But given the new battery is already drained I'm thinking something else might be up. Thoughts/Advice?

 

[BH_MTL]

Wondering if anyone has an update to this or more information. I have a 2018 GLC300. Last year got the noted critical battery warning light. Car was three years old and battery was indeed drained, so thought it must just be time for a new battery. However this week, with just a one-year old battery, the warning light is back. Last year, prior to replacing, I did check the alternator (Full disclosure: I'm not a mechanic, but YouTube made the task easy enough) and from my non-educated-youtube-trained evaluation, that seemed to be working OK. But given the new battery is already drained I'm thinking something else might be up. Thoughts/Advice?

The "battery monitor - charge status critical" issue has been going on for... years in my case. I have a 2019 GCL 300. Got the car in March 2019, problems started in October 2019.
1st visit: there is nothing wrong (Nov 2019)
2nd visit: we'll replace the faulty battery. (Dec 2019)
Problem stared again in late Feb 2020. Came back from Europe, COVID started. Gave up.
Fall 2020, as soon as it's colder, the problem starts again.
3rd visit: replace the battery
... Fall 2021: again!
4th visit: last week, got the car back 10 days ago. Oh, it must have been a defective battery.
Today... 10 days later (yes, I did drive the car...) the problem is back.

So: no, I'm not really happy.
Having the remote starter in the winter is useful, except it never works because of the battery problem.
48hrs ago, the Mercedes Me services expired (3 yrs) and I should pay to get access again. Not worth it if the battery is always faulty.

Really tired of this situation...
I sent the image of the warning message to the service manager. We'll see where we're going with this.

 

[Tony Mac]

Thanks Joe - please let us know how you get on


I have the same Warning message.

it stops if I take the car for a 1+ hour drive up the motorway, but returns within a few days. The car is 6 yrs old, so could simply need a new battery. But after reading yours and other owners posts about this issue I’m worried it might well be something else

Tony

 

[CHRIS-89]

Hi there, I am having this exact issue also on my 2017 GLC 250d which I drive 50 miles a day for 2 hours on varying speeds of 30 - 60mph. Initially I replaced the battery and all seemed good until about 6 weeks later I got the same battery critical error. I decided to unplug the sensor on the negative battery cable, start the car, turn it off, reseat the sensor and then start the car again, to which the error was gone.

Unfortunately, after exactly 6 weeks to the day the error message came back. I immediately though it was a coincidence so I did it all again, and lo and behold, after 6 weeks, the same message shows it's face again .

By this point I was convinced that the sensor or negative cable might be faulty, so after a bit of looking I found a second hand replacement off Ebay for £18.

Would you believe that after 6 weeks again the error is back 🤦‍♂️. Now the next thing i'm going to try is probably the auxillary unit in the passenger footwell but other than that I'm at a loss.

The strange thing is that even though I get this message every time I get in the car, it always starts fine in any temperature, even below zero.

Hopefully someone on here might have had some luck or knows something else that I could try.

 

[BH_MTL]

Here is an update....
They replaced the battery for the third time... since apparently, there was an error message pointing to a faulty battery. How can I be so unlucky.
Oh well, from day one, I have been insisting they run tests to see if there is a battery drain. Still not done.
Believe it or not, 6 days later: the the same battery critical error appeared! Car has been in the shop for the last 3 work days...
They found that the dribver-side headlight electronic module had a current leak, draining the battery.
The part should be in the shop as I'm writing this, so maybe the end of the story is coming. I will update the story whatever happens.
Moral of the story... they need to put an experienced tech on this and do real troubleshooting.
Good luck !

 

[bukzin]

It’s been a few months now…. still have issues?

Also, in terms of CCA (cold cranking amps). what size batteries are most folks installing?

 

[Valente]

possível solução:

 

[maldoman]

Go to know, many thanx

 

[BH_MTL]

It has been a few months since the headlamp causing the issue was repaired. Still no more battery issues.
Glad this is resolved...

 

[dluomamqt]

2021 GLC 300. Battery critical warnings started in 1st year. Diagnostics normal - " see if it recurs"
Problem continued (actually dead once). Recheck- normal diagnostics, replaced battery "because some problems reported with some batteries"
Problems recurred- normal diagnostics- basically "good luck"
Problems recurred maybe a month later, more frequent to now 1-2 X/d to once every 4 days, regardless of storage, temp outside, usage,
Battery voltage at 14.6- 14.7 while running, with no drop when revving engine. Can't read voltage until computer boots up, but with quick restart could see voltage drop to 6, then climb up to 14.7. Ran X 10 min- restart showed drop to around 12 then back to 14,7. Turned off and got a critical battery message 5 minutes later. I hadn't run it long enough for overkill assurance on charging , but I've had alerts a short time after longer drives in the past. At least the voltmeter drop was less, so I'm guessing it was charging some.
Scheduled for another look in 3 days. Service manager said they were in contact w/ MB last time- apparently they can do more detailed analysis (but I thought they had when everything was "normal"
I'm thinking the battery is ok, the messages aren't false and there's something draining when car off. Something in the computer code? Sensor/ connector issue somewhere ?

 

[Tony Mac]

We were seeing the same warning message, even after replacing the battery.

Other UK based owners have reported similar Battery Warning messages, and found the fault was linked to the Secondary Start / Stop Capacitor Battery - not sure if you have this in the US?

Replacing this secondary battery capacitor fixed the warning message + re-enabled Start / Stop functionality. I didn’t like the annoying Stop / Start and just lived with the warning message when getting in and out of the car.

We sold the GLC today - very good car

Good luck and please let us know when you get the fault fixed - sure it will help many other GLC owners

Tony