mmesce

e220d amg line 2016.

My brother needed me to nip over and jump start his wifes car today, so before i went over i checked under the bonnet to see where the battery ports were. I noticed the positive was visible but the negative looked under the plastic cover. I removed the plastic cover, 2 plastic spin clips and it slide off no problem. I located the battery negative under the filter housing. I returned the cover and clipped it back in however i started the car up and all of a sudden it stated "Auxiliary battery malfunction" in red on the dash.

At this point i turned it off, went back to the cover i just removed and re-seated it. I checked to see if there were any contact sensors and couldnt see any. The message was still on the dash except this time it wasnt in red it was in white. I took my wifes car and used hers to jump start my family members car. I assumed it may need time to clear so i went back to the mercedes and it was still showing this message. I took it for a 30min drive locally then restarted hoping the message would disappear. Its still there.

I've researched replacing this aux battery but i think it doesnt require replacing as everything works, nothing is affected and all i did was remove and reseat the cover. Im a little perplexed.

Any help or info on this is greatly appreciated to save me a trip to the dealers.

MWmp5

I believe this is what you need to replace.

FOR Mercedes/Benz Mercedes W213 E200 E250 E300 E350 E400 E43 E63 AMG Voltage Converter A2059053414

My 2017 E300 does not have an actual separate auxiliary battery like my 2011 E350 (which i replaced).

mmesce

I was kind of hoping not to do this but ill order it today. £50 less for non mercedes part, hate doing that but im not paying inflated prices.

Thanks for your reply.

mmesce

One last question. When I disconnect the battery to fit this thing will give me issues or will the car remember all the settings etc? I’ve read just need to re sync the windows...

ua549

Make a backup of your profile to retain navigation and entertainment system settings. I do it every time my car goes in for service. There is a menu item to do this.

MWmp5

You can also set up a 12v back up power source before disconnecting if changing battery. BUT if you are only changing the voltage regulator I dont think any back up is needed. You may want to Google that or checking Changing Voltage Regulator on this site

ua549

A profile backup takes only a few seconds. I make one every time I change a setting.

MWmp5

Where or how do you do that?

ua549

With the ignition on select:
Home Menu
System
System Backup
Import or Export
Device - memory card or USB device

I'm not sure if one selects import or export first or the device.
My memory is fading with age.

MWmp5

Thanks

mmesce

All the guides for changing that voltage capacitor state to disconnect battery so I will do, I’m not changing the battery just disconnecting it for this installation.

I'm out of warranty and don’t fancy paying £150+ for the part then an hours labour. It will be too much considering I’ve got the aftermarket part from xenons4u for £75 and every guide I seen says it’s diy job in passenger well.

I regularly backup and sync to the MercedesMe for my profile but stopped syncing recently as the cloud backup stated it had new settings and to sync then it put default German on my car :o so I’ve stopped doing the sync but I’ll manually backup first. I was just worried about key fobs etc

mmesce

Just thought I’d give this thread a conclusion...

Since Wednesday been waiting for it to stop snowing or raining for good couple of hours so I could give this a go.

It’s supposed to be a 45 mins job, it took me 2-3hrs. Part of this is because I’m a beginner and the other part is the quality of the e class. The xenons for you guide and video is what I followed but the only issue is that the video is of the same part replacement on a c class. The video shows the c class carpet can be pulled back partly however the e class carpet is too stiff and won’t bend without snapping it or damaging it. I had to take the whole front passenger carpet out of the footwell and although it’s not a big job it’s extremely annoying and it’s so compact and needs a lot of jimmying to get it out then back in. It’s also a heavy piece of carpet with lots of memory foam insulation on the other side.

It was a satisfying experience and this fixed the issue and it never caused any errors. I did disconnect the battery and I backed up command settings but in reality when the battery was connected back up it was like nothing had happened except that stupid auxiliary battery malfunction message had gone. Took it for a 30 min spin to check everything worked and all good. Thanks all.

sabre3

I had mine replaced at the dealer as warranty work. My settings and profile was still there also. Now my eco start stop works regularly.

mmesce

I’m out of warranty but I think if I tried I could have got them to honour it as I’ve only ever had it serviced and mot’d at the dealer. Didn’t fancy the argument as lots saying it’s a wear and tear item meaning they’d never replace it at £150+ and I hate taking it in.

skipper49

I have plenty of room on my music sd card, can I back up my profile to that card or does it need to be a separate one? Seems like using same card would make it so easy.