Hi guys, on my way home, I got a message on the dash "Auxillary battery malfunction"

Car is still under warrenty so call to dealer tomorrow.
Anyone know what the issue is?

My car is a 2015 C63s Sedan.


Cheers!

 

... there's an auxiliary battery?

 

Exactly!
But my stop start hasnt worked for about 3 months, always yellow on the dash. I gave up after it went back 5 times to fix it, getting the car back and it lasting a couple of days.

 

Wow... what did the dealership say about that? What a shame... such a great car, yet so many customer service issues popping up on this forum... of course, that's the point of the forum, but still. Sad to see these issues are not being addressed better by MB.

 

I saw this on my 2015 C63S a few weeks ago. Brought it to dealer, and they change the auxiliary battery. No recurring warnings, to this point.

 

Car is booked in but they can not look at it until the 17th so have to put up with the annoying message for a week.
Where is the auxiliary battery as its not in the rear?

 

Just had the "Auxiliary Battery Malfunction" pop up on my dash this morning. I traded texts with my service rep at the MB dealership, and she said it's the battery used for "Eco Mode" which I'm assuming is what supplies the charge for the stop/start feature. She said the car should operate normally (as long as I'm not using that feature) and that there is no immediate rush to take it in right away.

 

I went a couple of weeks before servicing mine, and I had no issues. My service advisor said that it is not an urgent issue, and your car will not shut down or anything.

 

My stop/start hasn't worked for months. Been in the dealer many times. Had an active engine mount changed, the main battery changed, software updates etc., only to have the car returned with it working (Icon green) then a few days later, back to yellow. Its been yellow now since June! I can drive an hour, do 100 miles and it might work.
I am wondering if this "Auxiliary battery malfunction" is actually the original reason its never worked?

 

Well, I HAD no issues... Auxiliary Battery Malfunction light came on, again, only a couple of weeks after it was serviced. Back to the dealer I go.

 

This just happened to my ‘15 with 28k miles. Getting it replaced soon, more for the annoying messages on the dash since I turn off Eco mode as I start the car.

 

Ive had my auxiliary battery malfunction for a couple weeks now. I had it a couple months ago but it went away. Just returned again a few weeks ago. My "eco" button still works. Car will turn off when at a stop (god I hate this feature). Any ideas what could be wrong?

 

Most Tunes, have the option to turn this off (disable it completely)

 

check contacts on aux battery, and replace if necessary. its super easy

 

Hi All,

This message just came up on my 2015 C63s. Is there an actual auxiliary battery or is it a capacitor?

 

Mine came on about two weeks ago. I also got key fob battery low message around same time. I changed the key fob battery and the auxiliary battery malfunction message went away. Hopefully the auxiliary malfunction doesn’t come back. MB service charges $280 to $450 after making some calls.