Auxiliary battery Malfunction

[CrazyArtLady]

Hi
The dashboard is showing the Auxiliary battery is malfunctioning.

it’s a 2016 E220 Estate. It’s been a brilliant car to ferry me and the two large dogs about. But the last 6 weeks been iffy.

I have been to 4 garages just to get some info and then thought let me check the car forum.

Over lockdown I had a few things fixed and done to the car and shelled out over a thousand pounds in total (service by Halfords and at a local garage replacement of the nox sensor). I am now at the end of the tether and tired of being ripped off. I am just an elderly woman and have no idea about cars. Times are hard and we all have to earn a living but not unscrupulously.

I was told by one local place not to worry it’s only ghosting. ???

Halfords told me the cost of the battery is around £250 plus labour extra so looking at £400 to £450. But if I am unlucky it could be the second battery which is dead too and that one is even more costly.

Another local place told me the battery is around £100. So with labour I am looking at £150 ish.

Mercedes Benz quoted me £98 for the battery and £250 for the battery and labour together. So about a hundred pounds more to the local garage.

my questions:

1. can I buy the battery and replace it myself (my neighbor may help if not too difficult).
2. Would I need special tools or special software to get the car going again?

3. And why does it have to be a Mercedes Battery? Why can I not get one from Bosch etc?

4. I was told each time a battery is removed the software for the car needs to be reinstalled. Is this true?

5. Can I still drive it like normal or just to the garage?

6. where is this battery even located? On 2016 E220 Estate.

Thanks!

Dani

 

[brandwooddixon]

Oh dear. It sounds to me like someone has been taking advantage of you.

Mercedes dealers typically charge about £130 - £160 per hour, hence why most owners on here seek out independent specialists.

On a majority of occasions problems with the auxiliary battery boil down to it being low on charge, this tends to be due to heavy stop-start use and short journey times. Sometimes this can be cured by use of a battery charger. The auxiliary battery is used to keep some things working whilst the engine isn't running and the main battery is used to start the car.

In any case it's just a battery and can be easily replaced, without having to perform any software downloads (normally just reset the electric windows/sunroof fully open close positions - performed by actually opening and closing them waiting until you hear a low click whilst holding the button down.)

I don't know where the auxiliary battery is on your car, on mine I had to remove some trim in the boot, but even so its not beyond the abilities of the average car DIYer. I think I paid around £85 for the battery for mine from MB.

Where are you based? Maybe someone here an recommend and independent specialist for you.

Oh and in the meantime don't worry about driving the car as normal, although I would suggest that you disable the Stop-Start feature each time you start your car, just so that your not left embarased at any traffic lights.

 

[Tony Dyson]

I have a sneaky feeling the Aux battery in your car is in fact in the form of a capacitor pack but I will of course stand corrected, what you need is a competent MB Independant garage and there are many around, if you post your location, town/city I'm sure the members will post their recommendations, in answer to your questions;

1. can I buy the battery and replace it myself (my neighbor may help if not too difficult). Yes if it is in fact a battery and not the capacitor pack I suspect
2. Would I need special tools or special software to get the car going again? No

3. And why does it have to be a Mercedes Battery? Why can I not get one from Bosch etc? I use Tayna https://www.tayna.co.uk/ as do many other members check your battery you'll find it's a Varta battery

4. I was told each time a battery is removed the software for the car needs to be reinstalled. Is this true? No

5. Can I still drive it like normal or just to the garage? Yes

 

[onefortheroad]

The aux battery is in the boot. A 12v motorbike battery. That's why the message says aux battery . The main starter battery is under the bonnet.

 

[peterws1957]

Hi
The dashboard is showing the Auxiliary battery is malfunctioning.

it’s a 2016 E220 Estate. It’s been a brilliant car to ferry me and the two large dogs about. But the last 6 weeks been iffy.

I have been to 4 garages just to get some info and then thought let me check the car forum.

Over lockdown I had a few things fixed and done to the car and shelled out over a thousand pounds in total (service by Halfords and at a local garage replacement of the nox sensor). I am now at the end of the tether and tired of being ripped off. I am just an elderly woman and have no idea about cars. Times are hard and we all have to earn a living but not unscrupulously.

I was told by one local place not to worry it’s only ghosting. ???

Halfords told me the cost of the battery is around £250 plus labour extra so looking at £400 to £450. But if I am unlucky it could be the second battery which is dead too and that one is even more costly.

Another local place told me the battery is around £100. So with labour I am looking at £150 ish.

Mercedes Benz quoted me £98 for the battery and £250 for the battery and labour together. So about a hundred pounds more to the local garage.

my questions:

1. can I buy the battery and replace it myself (my neighbor may help if not too difficult).
2. Would I need special tools or special software to get the car going again?

3. And why does it have to be a Mercedes Battery? Why can I not get one from Bosch etc?

4. I was told each time a battery is removed the software for the car needs to be reinstalled. Is this true?

5. Can I still drive it like normal or just to the garage?

6. where is this battery even located? On 2016 E220 Estate.

Thanks!

Dani

If MB have quoted £98 for the battery it will be a standard small battery as onefortheroad has stated above. They are charging you an hours labour to fit. Your manual should show where the auxilliary battery is, but should be in the rear deck area possibly behind the side trim. If your neighbour can help its half an hour job including time to locate!. You can get the same battery on ebay for £50 - many suppliers. For God's sake don't take it to Halfords!

 

[Tony Dyson]

The OP needs to confirm whether it's a true battery located in the wheel well in the boot or a Capacitor pack located under the carpet in the passenger footwell as Mercedes Benz refer to both types providing the same functions as an "Auxiliary Battery" I know the C class W205 uses the capacitor pack from 2014 and as I wrote earlier, I have the sneaky feeling the E Class did the same.

 

[CrazyArtLady]

I have checked the manual and there is nothing in there about auxiliary battery. I also checked the battery Section. I checked the online car system and nothing either. i then checked the boot and there is nothing either. So it must be in the front somewhere.

It’s turning into a mission. I think I will take it to the garage who will do it for £150. At least they have the tools to get into it and seem to know what they are doing. And I get one year warranty on the work.

 

[Craiglxviii]

To confirm. My 65 plate 2016 E220 didn’t have an aux battery, but a capacitor bank (location unknown) and an oversized AGM main battery located in the rngine bay.

 

[Tony Dyson]

The Capacitor bank is located on the bulkhead under the glove compartment behind the carpet in the passenger footwell and is not easy to access, @CrazyArtLady did you look under the boot floor in the spare wheel well? if a typical wet battery it will possibly be in there.
My advice is still to seek out a reputable MB independant, you can always use the 'Mercedes Specialist Finder' at the bottom of this page.

 

[Craiglxviii]

Or, post your location and we can suggest a few for you!

 

[CrazyArtLady]

I am in South East London near Woolwich.
I checked the boot area. There is nothing. It’s an estate. So it has to be somewhere else.

 

[CrazyArtLady]

I would like to say that my main battery was nearly flat a month ago. So I had it changed for a new one. It’s more powerful and about an inch bigger than the old one. It would not fit into the space. So they wedged it in filling the bottom area with cardboard and a bit of cardboard at the side to stop it from moving. Then it kinda fit and they put the cover back on top. Due to covid I could not get a Mercedes battery. Still cost me £100 online and they charged me £15 for fitting.

could that have an impact on the auxiliary battery?

 

[Tony Dyson]

That's confirmation enough for me that it's a Capacitor and all the more reason you should use someone who understands MB vehicles better than most. I'm sure someone will be along soon with recommendations.

 

[LostKiwi]

If you want to take it somewhere reliable and trustworthy try AMF motors.
https://www.amfmercedes.com/

It's owned by a member on here @alexanderfoti who has an excellent reputation and specialises in Mercedes

 

[Tony Dyson]

I would like to say that my main battery was nearly flat a month ago. So I had it changed for a new one. It’s more powerful and about an inch bigger than the old one. It would not fit into the space. So they wedged it in filling the bottom area with cardboard and a bit of cardboard at the side to stop it from moving. Then it kinda fit and they put the cover back on top. Due to covid I could not get a Mercedes battery. Still cost me £100 online and they charged me £15 for fitting.

could that have an impact on the auxiliary battery?

No self respecting motor engineer would do such a thing! I would now question the battery type is in fact the correct type for the model you have, when you choose your independent MB specialist for the aux battery I would ask him to give the main battery the once over as well for your peace of mind. The replacement battery should not have had any impact on the aux battery but it is a possibility that the procedures followed for changing the main battery could have but speculation isn't really going to help you any. You did the right thing in coming to the forum, everyone here is only wishing to help and will not profit from advice. It sounds as though you've seen enough profiteers!

 

[Blobcat]

I would like to say that my main battery was nearly flat a month ago. So I had it changed for a new one. It’s more powerful and about an inch bigger than the old one. It would not fit into the space. So they wedged it in filling the bottom area with cardboard and a bit of cardboard at the side to stop it from moving. Then it kinda fit and they put the cover back on top. Due to covid I could not get a Mercedes battery. Still cost me £100 online and they charged me £15 for fitting.

could that have an impact on the auxiliary battery?

£15 for cardboard... an unsecured battery in an accident can do a serious amount of damage. The battery needs to be checked and if suitable for the vehicle correctly secured.

 

[Craiglxviii]

That's confirmation enough for me that it's a Capacitor and all the more reason you should use someone who understands MB vehicles better than most. I'm sure someone will be along soon with recommendations.

Agreed. I’d go a stage further, the replacement battery isn’t correct for the 2.1 litre CDI with auto stop start; the capacitor bank isn’t able to draw enough charge from it and so the aux battery warning is coming up.

Dani, where was the battery changed? They fitted an incorrectly sized battery for your car, without enough Ah capacity (and at £100 it doesn’t sound like it’s an AGM battery either, so not correct for the car’s auto stop start function to operate). They mis- sold you a battery then did a bodge job of fitting it.

I’d say you need the new battery replacing with a correctly sized AGM battery, and invest £20 in a battery charger/ conditioner from Amazon should you not need to use the car for extended periods.

 

[Craiglxviii]

£15 for cardboard... an unsecured battery in an accident can do a serious amount of damage. The battery needs to be checked and if suitable for the vehicle correctly secured.

+1. The battery sits in part of either front or rear crash structure. An incorrectly secured battery in a crash can become a ballistic object that the bulkheads are not optimised to protect against. Very, very dangerous.

 

[malcolm E53 AMG]

If you want to take it somewhere reliable and trustworthy try AMF motors.
https://www.amfmercedes.com/

It's owned by a member on here @alexanderfoti who has an excellent reputation and specialises in Mercedes

Agree, judging by her feedback the lady needs to find someone she can trust hopefully the car will be taken over to AMF

 

[alexanderfoti]

It does sound like other garages may have been guessing on your car.

The Aux "battery" is actually a capacitor pack underneath the glove box, as mentioned, and its a bit fiddly to get access to.

+1 on the rear battery being correct, it absolutely has to be secured down correctly and is an MOT fail having it loose and not clamped in.