Auxiliary Battery Malfunction
Thread Starter
Junior Member
Joined: Aug 2009
Posts: 34
Likes: 6
From: Newport Coast Ca.
S63 Cab,S550e
Auxiliary Battery Malfunction
Thanks for any assistance. If I do not drive my car for a week or so I get a message that states Auxiliary Battery Malfunction. Most times it goes away after an afternoon of driving.Today it did not. Will the trickle battery that came with the car solve the issue? Or does that only support the main battery? How long should that auxiliary battery last? Its a 2017 with 19,000 miles. Any intel would be appreciated.
Super Member
Joined: Dec 2005
Posts: 785
Likes: 113
From: Scottsdale, Arizona
2020 S63 Coupe, 2006 Hummer H1 Alpha, 2018 McLaren 720S, 2022 Porsche 911 TurboS, 2022 Tesla Model X
In S63 it is actually a capacitor, not a battery - but M-B calls it a 'battery' so they can dodge extended/CPO warranty coverage on it.
You can buy the part for around $100 but I believe it requires a M-B computer to match it to the car, so the dealer will nail you for that even if you source the part at cost. I was charged around $500 for the part and labor by my dealer on my 2015 before I traded it in, and wasn't thrilled about it.
You can buy the part for around $100 but I believe it requires a M-B computer to match it to the car, so the dealer will nail you for that even if you source the part at cost. I was charged around $500 for the part and labor by my dealer on my 2015 before I traded it in, and wasn't thrilled about it.
Newbie
Joined: Apr 2022
Posts: 1
Likes: 0
C43 AMG
Indeed - it's set of supercapacitors.
No, there is no need to use a computer to match part with the car.
If you know how to solder electronics - you can order supercapacitors for few $ and replacem them by yourself.
If you know how to solder electronics - you can order supercapacitors for few $ and replacem them by yourself.
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Newbie
Joined: Jun 2022
Posts: 2
Likes: 0
2018 GLC 350e
Same problem…what did you end up having fixed to solve it?
I’m waiting for the dealership to get back to me.
they have been terrible at debugging the issues with this car.
happy to have found some other posts with the same error. Looking for what you had fixed that solved the problem?
thanks!
they have been terrible at debugging the issues with this car.
happy to have found some other posts with the same error. Looking for what you had fixed that solved the problem?
thanks!
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Super Member
Joined: May 2009
Posts: 810
Likes: 182
From: Laguna Niguel
'94 SL600,'05 SL600,'06 S65,'07 E63,'14 E63S,'09SL600 all sold, ‘15 S65,‘18 E63S,'17 SL65, '17S65Cab
MB definitely calls it an Aux Battery, at least in the S65. I had it replaced about 3 months ago in my 2017 S65 Cabriolet. The symptoms were random accessory malfunction and Inop messages on startup. Replacing the Aux Battery solved it.
Super Member
Joined: Feb 2006
Posts: 772
Likes: 261
I was told it was under the rear passenger side seat in the cabriolet as oposed to the trunk. Was that the case with your S65 Cabriolet?
Super Member
Joined: May 2009
Posts: 810
Likes: 182
From: Laguna Niguel
'94 SL600,'05 SL600,'06 S65,'07 E63,'14 E63S,'09SL600 all sold, ‘15 S65,‘18 E63S,'17 SL65, '17S65Cab
I did not ask where it was, not my typical behavior. I would doubt it is trunk accessible in the S65 Cab, too many things in the way with the top well and mechanisms. There is no space under the trunk floor in an S65 Cab because the standard Burmester 3D subwoofer completely fills the space.
MBWorld Fanatic!
Joined: Nov 2010
Posts: 1,105
Likes: 106
Cars
Mine was put in when I bought my car
Mine is attached to the + and - terminals of the battery with eyelets, in the trunk. Mine is a MB branded unit and I plug it into my house every time I return home. I got 10.5 years out of my batteries but they both went down at the same time.
