Did you get the dreaded “Auxiliary Battery Malfunction” alert in your vehicles instrument cluster screen? In this DIY how to video, we’ll show you how to locate your Mercedes auxiliary battery and how to replace your auxiliary battery for Mercedes Benz after you get the auxiliary battery malfunction Mercedes Benz alert.
Mercedes auxiliary battery malfunction E350 (W212)
Our advice here should work for most cars that have an auxilairy batter installed, and should still be a good guide for your auxiliary battery replacement. It’s all a matter of knowing where your auxiliary battery is installed in your car. In the case of this 2014 Mercedes E350 (W212), we show you the Mercedes auxiliary battery location, plus we show you 2 other possible Mercedes auxiliary battery location spots.
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Auxiliary battery function Mercedes
It doe snot matter if you have an auxiliary battery malfunction s550, or an auxiliary battery malfunction e350, it is essentially the same failure mode of your Mercedes auxiliary battery. The purpose of the auxiliary battery is to backup certain systems of your car, and in the case of the Mercedes Benz w212, and other Mercedes models with auxiliary batteries, they supply power to the ECO mode system, which allows your gas motor to shut off while your foot is on the brake during traffic lights. Your Mercedes-Benz w212 auxiliary battery also provides power for the hold function on your brakes.
Auxiliary battery replacement Mercedes W212 models and more
For some Mercedes owners, just finding where the auxiliary battery is located in their model is have the battle, and some have full sized motorcycle type batteries, while other Mercedes models have auxiliary batteries the size of a chuck of fudge. The three likely locations for your Mercedes auxiliary battery are the trunk for the Mercedes W212, which is another name for the Mercedes E350 models of a certain model year. Another location for your Mercedes auxiliary battery is inside the far left driver’s side dash panel, and way up under the front passenger side lower dashboard behind the floor carpeting. The Mercedes auxiliary battery replacement is quite simple, you just have to unscrew the power leads connected to the auxiliary battery, and replace it with a new Mercedes auxiliary battery.
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Where is the auxiliary battery in the 2014 350E Wagon
Had the same error on my E220 CDI today, your video was brilliant
thanks for the advice.
Thanks, very informative
I cant charge this battery right ?
Just buy i new one right?
Will the auxiliary battery malfunction prompt cause the check engine light to pop up?
Just wanted to thank you for this great video! I did this replacement using it and it was a "slam dunk" ! The replacement battery was purchased at an AutoZone store and included the extra hardware required to complete the install easily. The did charge me a refundable feel for the "core charge" but got it back when I turned in the old battery. Once again, thanks for your help and the savings of Big $ if it had be done by a dealer!!!!
No need to disconnect the main battery before replacing aux battery? Thanks
Where is battery for 2004 Mercedes CLK 500
The question guys if the exility battery malfunction pops up later on if you do not replace it will it kill the battery of your vehicle the one you keep in the front engine will it cause it to die? Any fee back would be grate
Remove negative cable first. Always! Why does no one know this?
Hello, I just replaced the auxiliary batter form E350 but still getting the message of low auxiliary battery ? Should I reset the computer and how ? 2006 Mercedes E350
I have the same car, is it possible to connect subwoofer amplifier (150w) to this battery or do I have to do it trough the main one in the front? I guess they are connected together or? Anybody? Thanks
How many auxiliary batteries does a 2014 ML350 have? I replaced the one I found by the spare tire with a Duracell (dura12-1.3f) 12V. I also checked the main battery area under the passenger seat but there wasn’t one their. I’m still getting the same message of aux battery malfunction. Do the Duracell batteries come uncharged?
I took mine out and it read 12.7 volts, 79%. I had this replaced at the dealership in 04/2018 and getting the Auxillary Malfunction message? Should I replace it?