Mercedes Auxiliary Battery Malfunction - Solved

In this video I am showing the way I am dealing with Auxiliary Battery Malfunction problem.
This is unfortunately quite common issue across entire Mercedes model range. Dealership offers option to take back the old unit and take some ££ off the new one.
When this issue starts, I highly recommend to take care of it as soon as possible. You can still use your vehicle without an issue, however if your main battery will fail for whatever reason, you will be stuck. The main function of this Aux Battery/Capacitor is to hold enough charge to serve critical electrical components of the vehicle such as gear selector.

[@-vg3fi]

Very good video which explains all the factors involved for this situation. Well done Tip Top Mechanic.

[@edwills9965]

Brilliant. Really helpful. Fixed it like a treat!

[@MrMessyb]

Thanks for the detailed and instructive video

[@martindance5873]

Very informative, you tell us everything we need to know about it.

[@adnan8258]

Really informative video mate thanks

[@ihorlevit5369]

Thank you! Very useful information

[@yunusyasar81]

It is extremely helpful and saved me couple of hundreds Euros. Many thanks Tip Toc Mechanic!

[@MusicodeDios4ever]

Thank you for this information.

[@zdenekmasek9643]

Hi, what type of connector on cable harness side is used? Some number has to be printed on it.

[@vasisasa]

Hello, where it, s situated this converter in a MB. E 220 cdi W 211, year 2006? Thanks.

[@harisyoung4110]

Hello, did the w203 model got this auxilary battery ? i seem can't find it where it located.

[@paulrollason908]

hi i’ve got a class w178 is the r Regulator in the same place. would appreciate any advice thanks

[@paulcollins4498]

you show brown as earth and red as +12v. what is the red and blue wire for coming from the regulator

[@lesleybell5915]

Hello - Mercedes A180 diesel automatic - does it have one of these? I've replaced everything... Still says see workshop - battery/auxiliary battery

[@johngodwin7751]

Thanks, very good😊

[@babatool]

Gla200 were I can find battery

[@kashf8694]

thank you well explained

[@TheMcs33]

What do u go on to check on scanner

[@240drea]

Is the battery capacitor and voltage converter the same thing?

[@khloekoolandmommy2368]

Can I do this myself I have a 2016 glc 300 Mercedes

[@syednaqvi304]

Do i need to disconnect main battery before doing this

[@catalinpantiru9828]

hi, can you provide to us the model of AUTEL diagnostic tool ? thank you.

[@amharali]

Could this be the issue if the comand system stops working randomly and turns on itself? Also reverse camera stopped working and the traffic sign system also stops working sometimes. I've replaced the 12v battery but the problem still happens but less often now

[@zionxnoiz]

Did you ever fix your problem?

[@amharali]

@@zionxnoiz yes, I had to get the command unit replaced. Not the screen but the actual unit that sits behind the centre console

[@jasiendjijawoe6662]

@@amharali i had the aux battery malfunction for a few weeks now and my COMAND turned off yesterday and wont turn on, i guess my COMAND may be broken. did you get a new one or second hand one from the internet? incase you got a new one, how much did it cost you?

[@amharali]

@@jasiendjijawoe6662 second hand from eBay. Then had to pay a local independent Merc specialist to program it so that the car accepted it. Btw I never had any battery related fault codes, so maybe yours just needs to be reprogamed

[@Rockleotube]

How can I get the genuine parts of Mercedes

[@HandsomeChris914]

I’m having fluctuations up 14.9 down to 13 I just replaced. My main battery. Was thinking on replacing this. Hopefully it would fix there isn’t too much information about this.

[@samsonadebisi7102]

Hi, i have change my c300 auxiliary battery yet i still get the auxiliary battery malfunction on my dashboard. Please help am frustrated

[@tiptopmechanic1155]

Is the new battery charged ? Is it charging at all ? Check fuse and if +12v are coming in. Is the battery new ?

[@youngbully87]

I have the same issue I replaced the aux battery in the trunk but still have the malfunction warning and the collision assist and lane assist coming on the screen

[@billmcquitty719]

Changed out auxiliary battery but after notice but notice still there after replacement any ideas??

[@DrM1107]

I have the same issue. It still says auxiliary battery malfunction.

[@kevinmetcalf6371]

Tks bto

[@wsem8802]

Just fitted a new one but massage didn’t disappear any idea ? Thanks

[@samsonadebisi7102]

I have same experience...can anyone help

[@alexandrubedreag158]

hi, did you sort it? if so, how? thanks @@samsonadebisi7102

[@alexandrubedreag158]

hi, did you sort it? if so, how? thanks

[@bluerunmotovloger8439]

Is tht c200 coupe..

[@ayaazsajadkhan]

I’ve replaced this, but still same issue is the actual battery I’ve changed my battery in the engine

[@juniorosias7228]

I replace mine it still dnt work

[@tiptopmechanic1155]

Check fuse in the trunk first. Measure is there is power comin in to the battery when engine is running. Is it brand new one or uses from.Ebay?

[@Albanian7]

@@tiptopmechanic1155 i changed and still the auto start/stop system doesnt work and message on the screen. I found the fuse is blown, i changed 10x the fuse and keeps blowing.. i dont know what to do

[@tiptopmechanic1155]

@@Albanian7 one of yor cables is damaged somewhere and is in contact with metal part of chassis. The moment you change fuse and power gets through that cable the shot circuit takes place and blows your fuse. Or the unit itself has short circuit and that keepa blowing your fuse.

[@Albanian7]

@@tiptopmechanic1155 i checked again, i took aux battery off and put new fuses, left car running no problem. I then inserted the new aux battery again and it blows its fuse (448) straight away. Could it be the new auxiliary battery mercedes gave me faulty? Or still short circuit? Thanks for replying

[@weloveledlights4302]

What shit cars same issue with my shitbox

[@pimp1979robertmack]

Don't listen to this dude... he said is not a battery it's actually this capacitor.. he's absolutely wrong and the auxiliary battery is above the passenger side rug..I hate when people come on here thinking they know what their talking about

[@bluerunmotovloger8439]

Is tht c200 coupe..