jamcclureuk

So the past few days I've been getting the "Battery Protection Coven. Functions Temporarily Unavailable" malfunction message on my '04 CPO E55. I decided that since I just got the only a couple weeks ago that I'd stop by the dealer to have them check it out. I've got 2 years/100,000 miles warranty so I figured why not.... Well, 2 hours later, the dealer tells me that I probably have a bad battery. He didn't tell me which one but I told him that I would just replace it.... He informed me that I shouoldn't do it because it's not just that simple...

Depending on which battery it is, can't I just buy a new one? He seemed to imply that if I pull out the battery and put a new one in that I'd would need to have my system reset by the dealer. He said that they get calls all the time because people think that they can just swap out a new battery and end up screwing it up.'

I personally think he full of sh*t.

Please advise. Thank you!

_____________

Edit.

Upon further reading I now know that the SA was not completely honest with me. (either that or he thought that I was completely incapable of swapping a battery).

Is there a list of batteries that MBWORLD members use/recommend in their E55's?

izzyz28

Buy a group 78 battery for the main and a BS-14 battery(motorcycle) for the auxiliary battery up front. Replace them as a pair since you don't know the health of either. The only resetting you'll have to do is run the windows up and down to the stops(hold the button fdor a couple of seconds at each stop), do the same with the sunroof(you'll have the hit the button 20 times or so to move it back all the way), and start the car and turn the steering wheel lock to lock several times. Thats it.

I am personally using a main battery from Wal-mart($78), and a gel cell BS-14(~$80) also from Wal-Mart.

LT1

About to change out my rear battery. Any radio codes etc to reset?

novae500

have you tested the voltage on the batteries yet? if so, you might want to consider getting a ctek battery charger. I left the fog lamps on last Sat night and didnt take the car out again until Sunday 440pm. Dead, nothing worked. I have a ctek but didnt think it would charge in time for me to go to work monday. So i picked up a battery at the local advance auto for $150 for the main battery. 3yr full warranty, 84 month pro rated. Took out the OEM one and put the new one in. Reset the windows/sunroof myself.

I still need to pick up an auxillary one or just will charge it w/the ctek.

Nasty50-Five

I had similar issue with my car. I ended up replacing both batteries since they were 5 years old anyway. Turned out to be the alternator though. My symptoms were that the sun roof, windows, and radio would stop working, don't know if you have these issues too.

03'55AMG

Wont replacing the batterys put the radio in lockout mode or w/e? Lost my manual and wouldnt want to go without radio

offolly

i need help . ive changed my two batterys and the Voltage Regulator, and tested the alternator , and still only 11.5 voltes to the batterys.. ?
what next . help

bobgodd

Check your battery control module, near the trunk battery. If you have an older P/N: A 211 540 (27/42) 45, it probably needs changing out. It's not cheap though.

The updated P/N is A 211 540 86 45, but it's not cheap, @ about $550.

jamcclureuk

Thanks again for the help guys. My Aux battery started throwing codes over the weekend. I bought a BS-14 battery and voila, no more error messages. Thanks again!