Fob Battery
Thread Starter
Junior Member
Joined: Aug 2016
Posts: 67
Likes: 2
2019 MB E300
Fob Battery
Batteries in both of my key fobs die very quickly: within a month usually.
Does it happen to anyone else? What brand of batteries do you use?
I assume they are not covered by warranty.
Thanks in advance
Does it happen to anyone else? What brand of batteries do you use?
I assume they are not covered by warranty.
Thanks in advance
Senior Member
Joined: Jul 2013
Posts: 319
Likes: 28
2013 E550, 2014 GLK 350
You have keyless go, I assume?
If so - do a quick search, you'll see the usual suspects. Best solution I have used is take your push button start out. We usually get 6 months per battery though, not one month.
If so - do a quick search, you'll see the usual suspects. Best solution I have used is take your push button start out. We usually get 6 months per battery though, not one month.
Super Member
Joined: Feb 2013
Posts: 580
Likes: 62
From: Maryland
2013 E550 4Matic
Apparently if you don't use Panasonic brand in the fobs, they die very quickly. Must have a partnership with them to only work with their batteries... dunno. The one in my fob now is Panasonic and it works as it should, and it's been there over a year now.
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MBWorld Fanatic!
Joined: Dec 2003
Posts: 1,283
Likes: 126
From: Central Coast, CA
2020 X7 xDrive40i, 2016 X3 sDrive28i
I was told a couple weeks ago by a tech at the local MB dealer that there's a service bulletin on this issue. Apparently there was a big batch of keys made with a flaw that causes high battery drain. He suggested I ask the service advisor to test/check out my key and get it replaced.
I found that even after the change key battery warning comes on , my key continues to work for another 6 to 8 months without changing the battery. So it seems the battery isn't really low, just whatever system they use to detect a low battery state is buggy and reporting way too early.
I've also started using a slightly thicker battery. CR2032 which still fits and gives me significantly longer life (1+ years).
I found that even after the change key battery warning comes on , my key continues to work for another 6 to 8 months without changing the battery. So it seems the battery isn't really low, just whatever system they use to detect a low battery state is buggy and reporting way too early.
I've also started using a slightly thicker battery. CR2032 which still fits and gives me significantly longer life (1+ years).
Newbie
Joined: Jan 2017
Posts: 14
Likes: 1
From: Dallas
E350
I just replaced one of my FOB's batteries, I have something to confess. Remember to take off the little plastic tape on the bottom of the battery. 
I thought my FOB was bad because it wouldn't work after changing the battery. Took me a couple of tries to figure out it had a protective tape on the bottom. DOH
I thought my FOB was bad because it wouldn't work after changing the battery. Took me a couple of tries to figure out it had a protective tape on the bottom. DOH
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
Just got my car back from the dealer. Told them up update Comand and keyless go. Not sure if they did the latter, but they changed the battery in the keyfob and I just looked and it was a Panasonic. I've tried several different types, Durcell, Energizer, Sony, but they don't seem to last very long. Guess I've give the Panasonic a shot, could be where the batteries are made, some of them were made in either China or Japan. Panasonic seems to be made in Indonesia. Or the eBay ones I'm getting are fakes from some cheap knock off factory.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Possibly, they're in the factory packaging instead of bulk like some really cheap places. But they're good about making fake factory packaging. Maybe they cut back on the lithium in the batteries. Voltage is good, usually 3.35 volts, but when you get the warning, they're down to 3.1 or less. Oh well, can't expect too much when they're only 50 cents each.
Super Member
Joined: Jul 2014
Posts: 992
Likes: 245
From: Tucson, AZ
'20 X5 M50i; '17 Ram 3500; Golf Cart; Bikes; Scooters
From the Service Bulletin Thread:
LI80.35-P-063677 - All models Keyless-Go DAS4 (2007 >) “Replace battery in transmitter key” reappears in instrument cluster within a few days after replacement, update KG control unit software/perform SCN coding. FYI if key enters passive mode resulting in no feedback from key during KG engine start key can be reset by removing battery.
LI80.35-P-063677 - All models Keyless-Go DAS4 (2007 >) “Replace battery in transmitter key” reappears in instrument cluster within a few days after replacement, update KG control unit software/perform SCN coding. FYI if key enters passive mode resulting in no feedback from key during KG engine start key can be reset by removing battery.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
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From: MA
2008 E350 4Matic, 2011 E350 4matic
That's why I had the dealer do a Comand update and keyless go the last time I was there. That was only a few weeks ago, we'll see how long the Panasonic battery they put in lasts. The ones I got were name brand, but you can get generic batteries for about 12 cents each if you get it in volume.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
What year is your car? The 2011 uses one CR2025, but you can fit a CR2032 in there. My 2008 used 2 CR2025, but it used a clip to hold it in and it won't fit if you use 2 CR2032's.
Thread Starter
Junior Member
Joined: Aug 2016
Posts: 67
Likes: 2
2019 MB E300
They also told me that the keys should not be stored at home close to each other or cell phone. Putting battery into the sleep node doesn't matter according to the advisor. I never had a problem with the key fobs from Lexus or BMW - the batteries lasted at least 1.5 years
Super Member
Joined: Apr 2016
Posts: 515
Likes: 99
From: Hudson Valley, NY
2012 E350
Just replaced my gob batteries. Not because there was any issue but simply because I've had my car a year now. Bought some Panasonic batteries on eBay, and it seems I'm good to go.
