FOB battery message
Thread Starter
Junior Member
Joined: Sep 2013
Posts: 60
Likes: 2
From: Vancouver BC
2012 C300 4-MATIC Sport, 2012 BMW X5 xDrive35d
FOB battery message
A message “Replace Key Battery” popped up on my dashboard 2 weeks ago. I replaced the battery in both my FOBs right away with Energizer CR2025. Yesterday the message “Replace Key Battery” popped up again. I’ve checked with both FOBs and in both cases the same message pops up.
I’ve checked voltage of both batteries and it is 3.04V and 3.05V.
What can be done?
I’ve checked voltage of both batteries and it is 3.04V and 3.05V.
What can be done?
Last edited by yober37; Dec 23, 2018 at 03:53 PM.
Senior Member
Joined: Jan 2018
Posts: 295
Likes: 24
From: Edmonton Area
2007 CLK550 Coupe, 2003 CL600, 2012
A message “Replace Key Battery” popped up on my dashboard 2 weeks ago. I replaced the battery in both my FOBs right away with Energizer CR2025. Yesterday the message “Replace Key Battery” popped up again. I’ve checked with both FOBs and in both cases the same message pops up.
I’ve checked voltage of both batteries and it is 3.04V and 3.05V.
What can be done?
I’ve checked voltage of both batteries and it is 3.04V and 3.05V.
What can be done?
It seems the voltage detector in the car is set a little high. As a side note, the CLK has two batteries in the fob, not just one like the c-class. Has anyone tried the MB factory batteries? They probably cost a fortune, but if their initial voltage is higher might be a viable option to avoid the hassle of changing them.
Has anyone tried the batteries from amazon? The ones where you get 15 for 12 bucks?
Newbie
Joined: Nov 2017
Posts: 6
Likes: 0
From: Taipei Taiwan ROC
2008 W204 C250 Avantgarde S M272
Here is my measurement to the CR2025 initial voltage by DMM:
1. Sony : 3.28V (Made in Indonesia)
2. Panasonic: 3.31V (Made in Indonesia)
3. Maxell: 3.31V (Made in Japan)
1. Sony : 3.28V (Made in Indonesia)
2. Panasonic: 3.31V (Made in Indonesia)
3. Maxell: 3.31V (Made in Japan)
MBWorld Fanatic!
Joined: Aug 2013
Posts: 1,364
Likes: 149
2012 C300 4MATIC Sport
My car was complaining about changing the battery in the fob so I used a brand new MB battery that I had purchased in 2014 which was manufactured in 2013, but the error messaged remained. I then bought a new VARTA one for $3 and problem solved. These keys are indeed sensitive to voltage. Could this be related to the fact that it's a keyless go car/key?
Senior Member
Joined: Jan 2018
Posts: 295
Likes: 24
From: Edmonton Area
2007 CLK550 Coupe, 2003 CL600, 2012
I just purchased new Energizers from WalMart, and the open circuit voltage is around 3.3 volts.
I also tried putting the remote in a steel mint box and it was still able to start the car using keyless go. so I am not sure how that is supposed to keep it from communiating with the car.
Has anyone with the rfid bag tried to use the keyless go with their remote in the bag?
I also tried putting the remote in a steel mint box and it was still able to start the car using keyless go. so I am not sure how that is supposed to keep it from communiating with the car.
Has anyone with the rfid bag tried to use the keyless go with their remote in the bag?
