2015 Mercedez Benz C300(W205) Auxiliary Battery FIX - IN REAL TIME

[@LivingTheReaume]

Thank you for doing this! Easily found and ordered the part next day on Amazon then easily switched it out in 20 minutes. $70 and 20 minutes of work at home vs $700 and leaving the car at Mercedes all day. That's a win in my book! Appreciate you!

[@LivingTheReaume]

For those looking, this is the part I got on Amazon - There are cheaper out there but this was available next day and 1 yr warranty - Bapmic 2059053414 Voltage Converter Module for Mercedes-Benz W205

[@chesca_jafarian_wings_life]

You have saved my life!! My daughter has her driving test tomorrow here in the UK 🇬🇧. Last night I realised that if there are any fault warnings, then the examiner will refuse to let her take her test in it. The cost including Labour costs about £300 + VAT (Tax). So I followed your instructions and bought a Auxiliary Battery, fitted it and had the garage do the code. All done at )75 + VAT. Real time video is much better, so keep them coming. Thanks again Francesca

[@muraad123]

Where did you buy it from. Can only find second hand genuine ones online in the UK.

[@zenfold7946]

For which model and which shop did you buy it?

[@joeleal77450]

Thank you so much for this step by step real-time video. I just replaced the voltage regulator per your video. Saved me a ton of money because the dealer was going to charge me almost $500 to do it and I did it myself having only to purchase the part for less than $100. I did not have a computer to reset the code, but once I replaced the regulator, the error message on the dash went away. Hopefully this takes care of my issue for a while. My car was a 2015 C300 4Matic. Awesome video. Saving it in my favorites!!

[@jar12347]

May I ask where you bought the capacitor from cause Im having trouble on finding the right one

[@joeleal77450]

Raj Patel bought it on Ebay. Did a search on the part number. Cost was $71 and shipped from China.

[@jar12347]

@@joeleal77450 Thank you

[@toddmiller8728]

Joe Leal was your eco start stop not working?

[@joeleal77450]

@@toddmiller8728 to tell you the truth, I don't remember because it was a feature that many times I would turn off. I just wanted to make the error message go away. Driving me nuts. Sorry I did not answer your question.

[@markymarkz8825]

I have a 2016 c300... bought the part on eBay for $60 bucks.. changed it myself using this video! The auxiliary malfunction message disappeared immediately. THANK YOU thumbs up 👍

[@admonkako]

Whats the part called please I need to buy one asap

[@ClevelandCeasar]

Part number

[@criticalbeautyvideos]

I have a 2016 MB C300 and the "Auxiliary Battery Malfunction" popped up an hour ago after I started the ignition. I panicked! Anyway, I took a chance and drove the car to the park to walk my dog. I googled for an explanation and found this KZbin video. I am not a mechanical person and I hate fixing anything related to cars, so I think I'll just take the car to a mechanic. Thanks for the explanation and demonstration anyway, Mario!

[@chrisvallin]

What’s up Rafa , did it work ? I also have a a 2016 MB...

[@korpharm]

Great video. I replaced mine in 20 minutes without an issue thanks to you. For those wondering I have a RHD 250d and as you would expect the auxiliary battery/voltage converter is on the other side.

[@OnlineWealthMaker]

This auxiliary battery is for the stop start function right? My A with circle always yellow until one day of driving then goes back to yellow after a day as far us not used much

[@ashJayden06]

Hi, can you confirm the AUX battery is on the passenger side when working on RHD cars?

[@aaftabriza7892]

Thank you. That helped a lot. Mercedes quoted $450. Did it for $138 my self. Appreciate it.

[@sollykhan2385]

Another fantastic video, Mario, Thanks for the time and effort to produce excellent tutorials, well appreciated, Bless 🙂😇

[@braddy3201]

Just copied your instructions and it was easy. I’m in the UK and the part from Mercedes was £110. Nice to save a few hundred more in labour by not taking the car into Mercedes. Many thanks for the video!

[@arthurfricchione8119]

Mario all your videos are top notch. I realize they all can’t be live but you do an excellent job with them thank you much for sharing 👍👍👍

[@johnchaffee3517]

This video was very helpful. I was able to do it in 15 minutes and hardest part was moving the carpet. Thank you for posting this video

[@frischersfitze5672]

Thank you so much from Germany! I needed about half an hour because simple mistakes and slow working, but it was really easy! In this half hour I saved about 400 Euros. You made my saturday.

[@knchen]

Thanks this was very informative! It's 15 minutes for those with the tools on hand and some experience removing and putting back the plastic panels, but for the rest of us it'll probably take an hour or two, including the time it takes to run the nearest Home Depot to get the tools.

[@VoltageDropDiagnostics]

Good job mario! And not editing this allows everyone to see the struggles we face getting these cameras into areas that we barely fit in ahaha! I’m liking that Launch too!

[@SuperMarioDiagnostics]

Yep the smallest thing can cause the biggest setback 😆 i loving this thing brother. Thanks for swinging by brother!

[@marky9223]

Thanks so much for making this video. I had the auxiliary battery malfunction error this morning when I got in my car, so with the help of this video, I was able to take the part out and order a new one. Couldn't have done it without you.

[@Julian-879-]

Excellent video. Great communication. Very professional. One of the best in North America.

[@ScienceOfDiagnostics]

Excellent video Mario, its pretty awesome seeing real time repairs. You have to be skilled and confident in your abilities to do that. Not everything is a 30 second fix. I'm always looking forward to what's coming out next.

[@SuperMarioDiagnostics]

Thanks brother for taking the time 👍 it's good for people to see that even simple things aren't just in and out and done . Thanks for swinging by!

[@gregoryrusnica7354]

I did the replacement on a 2016 C-300. The job went super smooth thanks to your video. Thanks Bro!

[@georgeziffer6550]

Thank you Mario. Your detailed video gave me the confidence and everything I needed to know to replace the aux battery (capacitor). The dash was indicating “Auxiliary Battery Malfunction.” Please keep up the great work!

[@rooduck]

Had this warning come up on my c250 , Mercedes wanted £166 to diagnose and then £397 to supply and fit the voltage converter, I bought the new part on Ebay from a proper Mercedes dealership for £100 and fitted myself in 40 minutes because of this video, Thank you Mario.

[@mradaml9934]

Hello, mate, same dilemma, however did you disconnect the battery beforehand? and did the error go on its own?, Mercedes is a rip off!

[@SuperMarioDiagnostics]

No i did not do either of those and the message clears on its own

[@mradaml9934]

@@SuperMarioDiagnostics cheers buddy, Great video btw. Much Appreciated.

[@PaulyD0859]

I’m loving your real-time videos. Most guys edit for time and it makes things appear to always go smoothly and in short time. The struggles of dropped fasteners are real! I’m also happy to see some of your Harbor Freight tools in action. All those people who don’t think HF stuff is useful in a production environment amuse me. I swear by their impact sockets and the Earthquake line of cordless tools. I abuse them daily.

[@SuperMarioDiagnostics]

😂 Yep all in man. Such simple things can draw us back lol. Yeah I'm pro-any tool that works! HF has some pretty good stuff, if it breaks, I upgrade. This earthquake line is great though! Hey thanks for watching bud!

[@followphilblack]

K 0:13

[@followphilblack]

0:16 😂

[@peterschardt7877]

Thank you for showing it to us, Super Mario! Saw it, understood it, did it! Consumers become fixers ... need more of that. Herzlichen Dank from Zurich, Switzerland.

[@CalumMorrison]

Great vid, many thanks - it worked for me. The hardest part was holding the carpet down, but no need to slit it, it can be kept out of the way to get the lower two 10mm nuts.

[@livingthetrolllife9498]

Thank you very much for this video, it made the replacement very easy for me. The notification I had on my dash was "auxiliary battery malfunction". Dealership wanted $170 for diagnosis and then parts and labor, would have worked out to be over $500 total and got away for $130.

[@fidibina711]

Can u plz tell me what code I have to put in after I replace it ?

[@livingthetrolllife9498]

@@fidibina711 no code was necessary when I replaced mine. Just drove around a couple minutes for it to notice the change

[@fidibina711]

Thank you soooooooo much

[@doug1950]

@@fidibina711 mine just reset on its own when I turned in the car

[@SuperMarioDiagnostics]

Nope, wouldn't matter

[@BO-ce4jn]

Great video, thanks so much. Quick question, is the auxiliary battery for an E350 in the same location?

[@Kalash9777]

On W205 Mercedes 2017, I had same fault code as you changed the small baterry like you did.. but i had stil the same problem and same fault code like you.. then i changed the 12V battery under the hood and it worked!

[@KewlQT]

Thank you for making this in real time. These aux. battery malfunctions are so annoying as they block your screen from driving out from where it happened. In my case my phone map malfunctioned, getting me lost in residential, at night, during -44 frigid weather!! What an annoyance!! Now that I'm at home, safe & warm, it's nice to know I can prevent this from happening again. My question is will changing this aux. 2nd battery prevent these light & other accessories that drain power from my car's battery since I do mostly short distance trips at periodic intervals? Love seeing every step with real good lighting & proper tools for a quick swap out. 👍👏👏

[@mikezerker6925]

Thanks for the video, this really helped me save a lot of money versus taking it to the dealer to fix! Next time u make a vid please include the part number in the description so I don’t have to keep rewinding and pausing the vid to be able to see it!

[@SuperMarioDiagnostics]

Lol take a screen shot 😆

[@masterkw3616]

It got me too! (W205 Juni 2014, ...004). With that video and a skillful hand it was fixed very quick. Thank you!

[@manjitmann941]

thanks mate. this is the second time it failed so replaced with non genuine unit and managed to do it all by myself thanks to you.

[@LMF5000]

Thanks for the vid. It's impressive how complicated mercedes made the car. It literally has a second battery buried deep behind two covers.

[@shumonjohnson6077]

Out here doing the Lords Work! Thank you!

[@stephenmarshall5302]

nice one Mario. I have done one of these last month and a motorbike style battery on another Mercedes this week. seems they are common! keep up the good work buddy

[@SuperMarioDiagnostics]

Thanks brother! Very common indeed. Easy fix, but Mercedes has a way intimidating the average person 😆

[@isaiasmorales8708]

Great step by step video.. made it simple to switch it out. The only thing that gave me an issue was the first cover. I bent the hook on the back a bit. Other than that a breeze.. thank you for posting.

[@hayzai]

Hi, thanks for doing this video. Do you know if the procedure / part is the same for a 2016 C63?

[@kopicxi13]

“Can’t go to auto zone and expect them to do it for you “ 😂😂

[@mickbridewell255]

Great video, got the parts and followed the video, the only issue i had was removing the carpet but otherwise done in about 30 minutes. Problem now solved, Thanks

[@austin1705]

Hey Mick , did the code disappeared by itself after you changed the part ? Thank you !

[@billrimmer5596]

Threat job. And very informative. How do normal cars start without that?

[@SuperMarioDiagnostics]

Yes no need for that since they don't use auto start/stop

[@AZFlyingDIver]

Thank you! The fix also exactly applied to our 2016 GLC 300...

[@bhavikbhatt1111]

How did you reset that message on display console thx.

[@allworld8059]

Was it the same part # as well?

[@gokok8553]

Good video. Do you have the electrical diagram of this aux battery? To which wires is it connected (like 87 maybe etc)> And can you give me the capacitance and voltage (surely must be over 14.4V) rating of the four capacitors (in microFarads/uF or miliFarads/mF or even if it is in the Farads/F range)?

[@GhaintJatt143]

How many miles we can drive with this code on I have same issue

[@zer0c00l44]

never fails to amaze me how a dropped screw will always be 8 foot from where your saw it drop

[@SuperMarioDiagnostics]

😂😂😂😂

[@normanclarke9587]

Great job explaining! It's probably the best I have seen so I had to subscribed to your channel.

[@orville58]

Unbelievable the things they put in cars and where they put them where do you go to find the location for modules. We have Mitchell at work but I have trouble navigating through it, of course I’m 61 years old and have only been learning this stuff for a little while thanks for the info and great videos keep them coming they’re a great help to me I’m going to try to make super Saturday

[@IAmWhatevaUSayIAm]

@Mario, i have a 2013 C250 Sport. It gave me the battery light yesterday then cleared on its own. Today the light came on again and the car turned off my stereo to save pwer i assume. I had the battery and alternator checked and the battery is good but the reading on the alternator said low voltage. I didnt get the dashboard message that says to stop the car and keep running. Could this be the Auxiliary power issue you had here or is this issue solely with the Alternator?

[@kellyspeppers]

Thanks for the video, always good to see you working.

[@anilmall7943]

Kellys Peppers I’ve change the battery converter and put the diagnostics clear the error Its working fine now not saying leave car in park it’s just that the stop start is not still working it something else

[@lowridermig]

Just like Mercedes "Here you have a battery for your battery" lol. Great video bud!

[@MarcMeyerA]

I found this super easy to replace by removing the carpeting from the passenger well, which requires unsnapping the plastic trim on the right of the footwell. Access to the panel is then easy and doesn't require unscrewing the panel above.

[@ozzstars_cars]

And another happy Benz owner goes down the road......and will be back soon with the next problem. haha Great vid Mario and thanks again for sending me your YT channel sticker! It's going on my tool box now. -Glen

[@SuperMarioDiagnostics]

😂 Thanks Glen! I appreciate that! .... This one had its first failure at 40k miles smh

[@odishoodisho4904]

Great one my friend. Which scan tool you think is more helpful for Germany car 🚗 ?

[@SuperMarioDiagnostics]

I've only ever used autel and this launch. Both are good for European cars.

[@simonbussey7530]

Followed the instructions thanks. There's a third nut to be undone you were missing. Also you don't need to have the code/warning reset. Mine went away after the first drive.

[@davidx9017]

You did a great job. So is my MB 2015 C300 4matic the same? Where can you find the location code? Thank you so much.

[@billyerds]

Perfect instructions. Took me no time aside from having to go buy a 10mm deep socket. :D

[@marvinjimenez3142]

Yes, i think that videos like this, help us to replace some part of our car, because on the dealership they charge a lot of money, even thought if the part is too cheap.

[@8power0]

GOOD ONE MARIO , THANK YOU .

[@edwardwainwright8651]

Thanks my friend. I have the 3015 c300 where the steering wheel broke in the up position. I can hear the motor running.ive read in the MB forum it's the "dog bone's. Can you show us how to replace it?

[@prchewwin23]

Great video. MB in OKC wanted $400. Ordered the battery for $160. Saved a bunch

[@qua2970]

Where did you ordered from? What's the part number?

[@NatalyasLegit]

Yes where did you order from?

[@SuperMarioDiagnostics]

I suggest you guys grab the oe part. The part number is on the thumb nail of the video.

[@doncarter1374]

Great video. Just had this problem and your video was super helpful. Not to nit pick but, you installed the cover over top of the removable carpet :)

[@ponakka]

Thanks for the video. I was suspecting this battery because the car does not start stop, but i think it is the bigger battery on the hood. Even with start stop enabled, car disables the function. Thats actually nice, but there has to be some reason why it does so..

[@SalemBinSaeed]

Thank you so much. Just fixed mine by myself. Dealership was asking for $450

[@xristosgioulountas4116]

The merchants in Greece told me that the w205 does not hane 2 battery thanks for the video I made it myself 🙏🙏🙏🙏🇬🇷👍💪

[@glennfarrugia7297]

Great video Mario I got this issue right now. Do you suggest a genuine replacement aux battery? There are some advertised on eBay also much cheaper but I’m concerned they might be not as good! Your thoughts please if possible? Regards

[@SuperMarioDiagnostics]

Always oem with Mercedes

[@sergekpan9823]

Hi Mario, Thanks for the video :) Please do you have a link to the part? Thanks!

[@ADONAIsays-so]

Thanks much for the video. What flashlight is that you're useing??

[@SuperMarioDiagnostics]

It's the braun from harbor freight. Thanks!

[@muebermuth]

Hello Mario, greets from Aachen in germany, I have here a S205 C300 hybrid from one of my customers, and the electrical vacuum pump received only 9,5Volt at nearly no current, so does the pump not work. Is the front sam left side of the component you changed in this video? Fuse 30 and 118 in the front fuse box do have the same only 9,5Volt. Any ideas? which code reader do you recommend?

[@MiguelMartinez-np8uo]

Thanks for the vid Mario you are the man! Question, why no diag on this issue?

[@SuperMarioDiagnostics]

Diag was already done prior to filming, and the focus of this video was simply on how to change the aux battery

[@SK-xg2kb]

Hi - I have a UK Right hand drive c250, Will my Aux battery be in my passenger footwell - that is the left hand side if you were sitting in the car? Thanks in advance. Great vids.

[@SuperMarioDiagnostics]

I couldn't say for sure, sorry

[@eugenekovalov9370]

Best video I found. Thanks!

[@mazenkanso]

Thanks for the video, the error disappeared once I changed the Voltage Converter Module, but on the screen the ECO light does not show up anymore and it does not start/stop even though the switch for ECO in the center console is on and lit green. Does it need some kind of hard reset. Thanks again

[@nawarna6794]

Great video. My OBD scanner is giving me no codes, my battery is still good and no issues when turning the car on. but I wanna verify the code before I buy the auxiliary battery. Do I need a special diagnostic scanner?

[@SuperMarioDiagnostics]

Yes, a code reader tends to skip over the modules that provide those codes

[@bhavikbhatt1111]

Even mine is gud and obd scanner not showing me anything but message is still there of auxillary batt malfunction. Let me know if u find some thing or something to get rid of this msg.

[@SuperMarioDiagnostics]

What scanner are you using?

[@robertkelly4000]

Followed these instruction and replaced this on my car using a Genuine Mercedes part.. Very straight forward however the warning message just will not clear. No issues with the car. Runs fine. No battery drainage, all electrics working fine and starts first time everytime. How do I remove the dashboard warning message?

[@lydiavillarreal5485]

Yes, I do have the same issue. I did purchased the part online and its not original but compatible. Please advise how to remove the warning sign.

[@SuperMarioDiagnostics]

What code did you have in the scan tool? If the code isn't exactly the same, it could be something else, as this light will come on for several codes.

[@lydiavillarreal5485]

@@SuperMarioDiagnostics I did not get the scan tool, I don't have it. I called the dealer when the " auxiliary battery malfunction" warning came on my dash. I replaced and is still giving me the alert.

[@SuperMarioDiagnostics]

You'll have no choice but to get it diagnosed. At the very least get that code read. Not any code reader will access that module either, has to be a pro level scan tool. Another variable is the part itself, I'd never put an electrical part into a Mercedes that's not original. These vehicles have circuit tests that have expected results, and if that part isn't up to EXACT specifications, it won't pass/work. Anything is "compatible" these days, but not everything is built the same.

[@lydiavillarreal5485]

@@SuperMarioDiagnostics Thank you Mario, I will do it and I do believe that might be the reason, I will order an original part also. Regards!

[@amandajane7726]

Thank you sooooo much for this video!! You’re a great teacher!

[@saqibkhan3193]

Hi great video! Changed mine but unfortunately message still coming up with fault code buffer battery of electronic ignition lock has a malfunction. Have you experienced this? Any help would be greatly appreciated

[@chasebills7156]

Just did this!👍 Hardest thing was to put the first foot well plastic cover back in when I was done.i was there for like 15 mins.in the end it just slides right in

[@asadansari7183]

Thanks for information and video. I really enjoy watching it. A A from Karachi Pakistan. 👍

[@zer0c00l44]

Ive got a 2015 mercedes c class blutec 220 estate and im from the UK so the steering is on the other side will the procedure for me be the same please and in the passenger footwell. Thanks in adbance great video btw real good

[@SuperMarioDiagnostics]

Should be

[@zer0c00l44]

@@SuperMarioDiagnostics ok thanks man appreciate the reply. 😁✌️

[@prospexican]

great video, mitchell was miss guiding me.

[@MAAZAD]

Thanks brother. But how do u reset the warning message/code ?

[@Fogrideriphone]

completed it today. thanks for the guide. C 450 AMG

[@tramelhines]

Thank you for your time in doing this video.

[@guillz925]

Just replaced mine thanks to you. Appreciate it

[@lstvictor]

Thank you so much for the real-time video. Please tell us what the part number was.

[@Beach_City562]

I love the video but I still don’t understand the reset of the codes?

[@davidarocho9575]

Hi mario listen i have a 2018 mercedes-benz C300 2.0l i change the auxilary battery and the stop vehicle leave engine running still on

[@dm9193]

Cool, do I need to disconnect the main battery before I attempt this?

[@Kalash9777]

I also replaced the small battery like in your video but after mine sais error back up battery then.. it sais stop car leave engine running.. i have the same error code as you had

[@prospexican]

will the warning message dissapear at cluster?

[@jzsanchez]

Thanks Man. I need to change the aux battery. I just need to find it. Where should I look for it? 2015 c300 4matic

[@SuperMarioDiagnostics]

Dealer only

[@mohammedabuabeeleh5918]

Hello Mario. The light didn’t go away although I replaced it with an OEM part from Mercedes. Do I have to clear the code for it to go away because I didn’t. I simply unplugged the main battery terminals for 20 minutes and plugged it back in. The code showed up after 30 seconds

[@suffyxx8662]

I have the same issue. Checked voltage on old and new converter and it's good on both. Anything else cause this problem?

[@mikeharris259]

Did you found out what else cause the problem

[@ParmG14]

Any solution to this? I replaced the part but the error message sometimes comes back on the dash, especially when reversing camera is activated

[@tonyrussell7243]

I am having the same problem. I’d love some help

[@albinchristensen6141]

I’ve read on forum that replacing the auxiliary battery or the start battery will need to reset and program/code the new battery. Is that incorrect? In your video you didn’t reset or program and it worked. I’d like to work on my car but not if it goes in to limp mode cuz I don’t have the computer/scan tool. Thanks in advanced

[@SuperMarioDiagnostics]

Not true. That's true if you replace the main battery, you must register the new battery, either way you'll need a full function scan tool in order to read the code from this module and properly diagnose it before doing anything else

[@albinchristensen6141]

Super Mario Diagnostics ok thanks. Do you still need to register the new main battery if you hook up a spare battery so the computer never shuts off? If so I might change the auxiliary battery my self using your video and letting the dealer chasing main battery. Sucks but what can you do :)

[@SuperMarioDiagnostics]

You're attempting a memory saver by doing that, and it's not why you must register a new battery. The reason the registration is required is to inform the power management system that a new battery has been installed. When that happens, the vehicle will relearn the state of health of the battery, and charge it accordingly. If you change the battery, without registering it, it'll think that the old battery is still installed. So it will overcharge your new battery(since the battery state of health is less than a new one, and it will never reach that of a new one) and likely ruin your new battery and alternator - over time. This is not a fast sequence of events, it happens long term. The vehicle constantly monitors the health of the battery, the amount of current your vehicle consumes while it's in its auto-off state, it's parasitic drain, etc. The registration resets these learned parameters and allows the vehicle to relearn them.

[@al-shayb2539]

I like what you did 👍🏼, but what you call that device you’ve changed

[@RosaHernandez-ot7vt]

Thank you! You have given me the confidence to do this myself.

[@mariusbutkus995]

any idea what that could be if I’m getting a red tripple battery symbol on the dashboard malfunction see owners manual . On my mercedes 2018 reg . C200 petrol ???? Is that the same thing I need to change like many of you done ? I’m talking about auxiliary battery voltage converter?

[@zlatko1234554321]

Hi, my media centre cuts off for a few seconds and comes back again while i’m driving, also freezes the radio volume and few other things, if i restart the car can fix the problem but for short period of time. I asked specialist and he recommend to change the Aux battery, will this really be the case? I have no messages and no red lights on the screen. Do you recommend to change the aux battery as well?

[@Sjaubi-qf6wd]

Will the car still function with this light stop the car from starting or will it stall while driving or while the car is idling ?

[@mmihir82]

Where does the ML350 2015 auxilary battery locate? Is it in cargo? or is it underneath the front passager seat?

[@BhanguARSH]

Hi We replaced the auxiliary battery But the massage is still there Stop vehicle leave engine runnig Please help me with this What else it could be

[@chrisryan8894]

If I don’t have a code reader to clear the code , will it reset itself after installing this ?

[@MrMiguel3087]

Cambie esa pieza pero sigue con el mismo código será la batería ? Mi carro es del 2016 y estamos en el 21 teniendo en cuenta que salió en el 2015 ya tiene 6 años de vieja esa batería

[@Knightrem]

Love it when I go to jump these cars to find the battery covered in water, I often ask the customer if they tried to fill up the cells and if they though more would be better.