Auxiliary battery malfunction after installing new battery in the car

[somdipdey]

Hi All,

My battery died so, I had to buy a new battery from Halfords and installed it. The car works fine but now, I get a notification on the cockpit dashboard that says "Auxiliary battery malfunction." At Halfords I asked the technician if this was ok, and his reply was, "yeah, it happens after a new battery is installed and the previous battery was flat. So, drive the car around more with this new battery and the problem will go away"

But I still get the same notification of "Auxiliary battery malfunction." How can I fix this (possibly spending any more money)? Any suggestions?

 

[geoffus]

You will still need an auxiliary battery, it may be a small battery in the boot or maybe a capacitor in the front, mine is kaput as well.

 

[OneForTheRoad]

Also worth checking the fuse in the boot is ok , it can cause error messages, especially on an e class .

 

[KillerHERTZ]

How To if you do need to swap it:

How To Change Aux Battery | HOWTO

My latest video, hopefully useful to anyone needing to change it: :)

forums.mbclub.co.uk

 

[BlackC55]

Bin off that Halfords battery and get a proper one on there. They don't seem to be of the best quality. We generally use genuine MB batteries because they last, work and fit correctly. To find out the cause of the issue, it will need to be plugged into a diag machine to guide you to the fault.

 

[flying haggis]

Varta or Bosch batteries are what I fitted ( I think one makes batteries for the other anyway!)

 

[rf065]

Varta or Bosch batteries are what I fitted ( I think one makes batteries for the other anyway!)

And, Halfords is the last place I would take any car to!

 

[OneForTheRoad]

I bought a Halfords 115 for my e350 , made by Yuasa by all accounts. Not a bit of bother over the 3 years , stop start never once went off , always green. I was desperate at the time and Halfords was the cheapest, I say cheapest ,it was £159 , now it's £203 .

 

[Deleted member 166119]

Hi All,

My battery died so, I had to buy a new battery from Halfords and installed it. The car works fine but now, I get a notification on the cockpit dashboard that says "Auxiliary battery malfunction." At Halfords I asked the technician if this was ok, and his reply was, "yeah, it happens after a new battery is installed and the previous battery was flat. So, drive the car around more with this new battery and the problem will go away"

But I still get the same notification of "Auxiliary battery malfunction." How can I fix this (possibly spending any more money)? Any suggestions?

This fault applies to the auxiliary battery, not the main car battery. I had the same fault on my C250 W205 the other day. Bought a voltage converter from amazon and fixed it no problem. On the W205 the auxiliary battery is in the footwell behind the carpet. This appears to be a common fault. Here is the link. https://images-eu.ssl-images-amazon.com/images/I/51La0XV6YWL._AC_UL232_SR232,232_.jpg
There are cheaper versions but the comments regarding them are not good.

 

[gr1nch]

This fault applies to the auxiliary battery, not the main car battery. I had the same fault on my C250 W205 the other day. Bought a voltage converter from amazon and fixed it no problem. On the W205 the auxiliary battery is in the footwell behind the carpet. This appears to be a common fault. Here is the link. https://images-eu.ssl-images-amazon.com/images/I/51La0XV6YWL._AC_UL232_SR232,232_.jpg
There are cheaper versions but the comments regarding them are not good.

Where did you install the voltage converter?

My 2017 W222 has a healthy aux battery but get the "Auxiliary Battery Malfunction" message and Distronic disabled.

 

[Deleted member 166119]

Where did you install the voltage converter?

My 2017 W222 has a healthy aux battery but get the "Auxiliary Battery Malfunction" message and Distronic disabled.

The voltage converter is next to the auxiliary battery behind the carpet in the passenger footwell. You can pull the carpet back a bit to reveal a large plastic cover that has three nuts securing it. Remove these three nuts to pull back the cover and you will see the converter mounted wit a single 8mm nut. Hope this helps,

John

 

[Deleted member 166119]

The voltage converter is next to the auxiliary battery behind the carpet in the passenger footwell. You can pull the carpet back a bit to reveal a large plastic cover that has three nuts securing it. Remove these three nuts to pull back the cover and you will see the converter mounted wit a single 8mm nut. Hope this helps,

John

This applies to W205 the W222 auxiliary battery is in the boot on the right hand side behind the panel

 

[Bayleaf]

Bin off that Halfords battery and get a proper one on there. They don't seem to be of the best quality. We generally use genuine MB batteries because they last, work and fit correctly. To find out the cause of the issue, it will need to be plugged into a diag machine to guide you to the fault.

Halfords don't make batteries they just sell them.

 

[rf065]

Halfords don't make batteries they just sell them.

They are a big enough to have batteries made to their level of cheapness though, no matter what is on the sticker.

 

[Fastcar155]

They are a big enough to have batteries made to their level of cheapness though, no matter what is on the sticker.

Hi , that could be said of any non branded part.