Red Light Flashing on Key
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 37
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'13 E550 Sedan, '15 S550 Coupe, '15 RR Autobiography
Red Light Flashing on Key
Hi all,
Recently my key started flashing a red light night the panic button every time I press any buttons (lock, unlock, open trunk). I read that this could mean my key battery was low but I'm not getting a warning when I start my car. Any ideas as to what this could mean?
Thanks
Recently my key started flashing a red light night the panic button every time I press any buttons (lock, unlock, open trunk). I read that this could mean my key battery was low but I'm not getting a warning when I start my car. Any ideas as to what this could mean?
Thanks
Super Member
Joined: Feb 2013
Posts: 580
Likes: 62
From: Maryland
2013 E550 4Matic
I'm responding to this thread because when I initially saw your username I thought it said "colon biter" which is my new favorite insult 
As for your issue, it probably is a low battery. I had a dead battery in one of my fobs and it didn't unlock the car or start it (I have Keyless-GO). I think it's a CR2025 battery, but I might be wrong (maybe CR2032). It's easy enough to pop off the back of the fob and check for yourself. If you don't have Keyless-GO, you probably won't notice this because you have to put it into the ignition slot and it should still work that way (my Infiniti fob worked if you put it in the slot, and it also had the keyless feature, so that's how I figured out that fob had died too).
As for your issue, it probably is a low battery. I had a dead battery in one of my fobs and it didn't unlock the car or start it (I have Keyless-GO). I think it's a CR2025 battery, but I might be wrong (maybe CR2032). It's easy enough to pop off the back of the fob and check for yourself. If you don't have Keyless-GO, you probably won't notice this because you have to put it into the ignition slot and it should still work that way (my Infiniti fob worked if you put it in the slot, and it also had the keyless feature, so that's how I figured out that fob had died too).
Last edited by blegthbloo; Dec 5, 2016 at 09:25 AM.
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 37
Likes: 0
'13 E550 Sedan, '15 S550 Coupe, '15 RR Autobiography
I'm responding to this thread because when I initially saw your username I thought it said "colon biter" which is my new favorite insult
As for your issue, it probably is a low battery. I had a dead battery in one of my fobs and it didn't unlock the car or start it (I have Keyless-GO). I think it's a CR2025 battery, but I might be wrong (maybe CR2032). It's easy enough to pop off the back of the fob and check for yourself. If you don't have Keyless-GO, you probably won't notice this because you have to put it into the ignition slot and it should still work that way (my Infiniti fob worked if you put it in the slot, and it also had the keyless feature, so that's how I figured out that fob had died too).
As for your issue, it probably is a low battery. I had a dead battery in one of my fobs and it didn't unlock the car or start it (I have Keyless-GO). I think it's a CR2025 battery, but I might be wrong (maybe CR2032). It's easy enough to pop off the back of the fob and check for yourself. If you don't have Keyless-GO, you probably won't notice this because you have to put it into the ignition slot and it should still work that way (my Infiniti fob worked if you put it in the slot, and it also had the keyless feature, so that's how I figured out that fob had died too).
So the light has always been blinking and I just haven't noticed it? The first pictures says the battery is working properly if the check lamp lights up..
Junior Member
Joined: Sep 2016
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From: Arizona
2014 Mercedes Benz E250 Bluetec
Well, I didn't see the red light flashing and the message on my dash about my key fob battery but my car couldn't find the key so I replaced it and it did the trick. Mine's equipped with Keyless GO.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,189
Likes: 1,548
From: MA
2008 E350 4Matic, 2011 E350 4matic
Well, I didn't see the red light flashing and the message on my dash about my key fob battery but my car couldn't find the key so I replaced it and it did the trick. Mine's equipped with Keyless GO.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
Junior Member
Joined: Sep 2016
Posts: 47
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From: Arizona
2014 Mercedes Benz E250 Bluetec
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MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,123
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Well, I didn't see the red light flashing and the message on my dash about my key fob battery but my car couldn't find the key so I replaced it and it did the trick. Mine's equipped with Keyless GO.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
How are you guys getting the Low Key Battery Warning messages, it never showed up on mine? Just says that it couldn't find/recognize the key at the time.
My car says "Replace Key Battery", which I understand it is telling me battery is getting weak. Everything still works fine at this point though.
