so I've been getting this battery fault constantly, sometimes the car sputters, loses power, dealer says its a low voltage fault but is unable to find why/what... been at the dealer for a while as they're trying to figure it out, shop foreman is involved, so far they can't locate the issue and are communicating with tech support at MB corp for guidance. They checked everything in the system and nothing is found faulty or bad, including battery, voltage regulator, ground, loose cables, alternator voltage output is good. my car is a 2018 with 1500 miles. this is very frustrating and upsetting!

 

Hi,

You have a OBD2 Dongle in?

Best Regards

Stenzel

 

I don’t, car is at dealer, the fault that they keep getting is some low voltage fault

 

Gil Berko / GilsE63s I noticed that you just picked up ur 18 GTR a few months back. Did the previous owner disclose any problems they had with the low voltage errors or was this slipped under the rug?

 

bought it from a dealer and no there was no such disclosure, i honestly don't think they knew about it, they just got the car from a broker who represented the seller, and my guess is this latent issue was unknown, of course my purchase was as is no warranty so there's nothing i can do about it

 

Check the wiring loom at the back of the car in the trunk where the First Aid kit is kept. Early cars can experiencing chaffing of wiring over a specific aluminum strut that is difficult to diagnose. This causes a short and can lead to all kinds of electrical gremlins.

Good luck!

Bish

 

Hi Gil/Gils,

Any news on this issue?

Are you running or disabled?

Bish made a good point in post #6. If you need help with it I can direct you to the spot where a potential short might exist. I just inspected mine from a recent laundry list of U-codes that suddenly popped up. I have a thread here on that issue and how I disposed of it. Mercedes did (and does) a terrible job with their CANBUS harnesses and terminations...almost high school project like.

The potential for a shorted hi/low CAN bus pair could exist at the rear SAM control unit (but it's not a common issue either), specifically at the BUS terminal. There isn't much that needs to be done to expose the BUS terminal and the inspection, by eye, is easy enough to do.

I'll leave this pic if you decide to check it out. But, remember too, if a short like this is found, you'll have to repair the short, then do a deep scan to clear all U-Codes that resulted from the short.

Here's where to look - Rear storage area, leftside, by the storage for the tire inflater, etc. Just remove the trim cover, no tools.



Yellow arrow shows the lower left corner of the rear SAM fuse panel for reference. Blue arrow shows the CANBUS terminal. Red arrow shows a POTENTIAL example and location where a databus pair could get snagged and short out to a grounded chassis part.

One final comment about Controller Area Network - All the modules in the car are nodes on the CAN bus. The CAN has a gateway router that works similar to the way the router in your home might connect and manage all of the "nodes" connected to it. Just like the router in your home, data streams can get corrupted and cause "various stuff" to start malfunctioning. The battery management module (the one now showing a malfunction in your car) might be perfectly OK, but lost its path on the CAN bus. That is why you must clear all existing faults AFTER a repair attempt is done, so you can reestablish network integrity.

The dealer should know this, but in my experience with all dealers with all makes, the techs are typically weak on diagnosis (real diagnosis), always strong on parts replacement. So, they can see a fault like this, immediately replace the battery management module, then get lost when it doesn't fix the problem.

Hope you keep us posted!

All the Best,

Acta

 

i have the same problem, and in the dealer dont know what hapend whith the car, i replace baterry and alternator, and the same problem apears, give a solution pleae!!!

 

….and Bish knows this because…..

 

lol

it never affected my GTR luckily but when I inspected that area, the wiring loom was under tension as it crossed over that aluminium piece. I made more room.

There was a very early US owner whose car came to a complete stop in Vegas iirc, due to this issue and it took some time for his Service dept to figure out what was going on.

 

Yes I remember coming across that thread, is this the one? https://mbworld.org/forums/coupe-roa...ml#post7363941

 

For all those who ***** and moan about the people who populate this forum - take a look at the help available from conscientious good-hearted people like Acta_Non_Verba.

 

Thanks I always find their threads very detailed and helpful.

 

Hi Gustavi - i see you're in Paraguay, is that correct?

Dealer was able to source a New, Mercedes OEM Lithium Ion Battery as replacement in your GT R?

 

Great timing on this thread. Just had the same error pop up three times in a 15 minute period. Had to pull over and restart my car. Going to take a look at the wires later today

edit: no issues with the wiring.. may need to take the car to the dealer yet again

 

Sorry to hear that, hopefully it is a quick fix.

 

maybe some need for a real pro ?

 

Hello Sir, please also link here your proposed service for this fix for Li-Ion to AGM (non-Li-Ion battery), and the fact that you can effectively and Remotely code out all Module/SAM requests for Li-Ion Battery, to make the AGM Battery fully operational in the AMG GT x line up.
Posting your price for this service would also be greatly appreciated.

Myself and others have heard of your exceptional work - thank you!

 

Hi !
$250
I code the conversion yes

BenzNinja members have 50% off
for those who don't have a system we also do rental
please ask other questions by online form on www.benzninja.com
Thank you !

 

Any update on this? Did you solve your problems? This happen to my 2020 AMG GTR as well i took it to the Dealer and they don’t know what’s the problem, and my friend ask them to change the alternator, the problem is fixed, but after one year this popped up again.

 

Check the wiring loom for a short in the left side of the trunk behind the panel where the ‘Emergency kit’ lives. Pay particular attention to any wires that run very close to any brackets you see.

 

Sorry to hijack the thread. Does anyone know what equipment that is circled in green? I’m my 18’ GTR it’s missing and unplugged

 

Sadly needing to jump on this bandwagon too. I'm having the same issue with my '17 GTR, oddly enough it's nearly always when I enter reverse and start parking up. I've got a decent OBD Reader which has thrown a historic P140471 on my exhaust. Not sure if it's related but given this seems to trouble a few people I'm putting as much detail in as I can! Checked the wiring in the photo's above and although the blue/white cables are quite tightly stretched, I can't see any breaks and it doesn't seem to be making contact with the bracket.

The voltage of the battery with both the car off / on is above 12v, and the car barely moved over winter and wasn't trickle charged (my car park has no outlets...) - so I don't think it's the alternator or even the battery given that the voltage is still decent.

The investigation continues!

 

Was the issue resolved? Are you getting your car serviced at a mercedes dealership?

 

Were you able to get this issue resolved?