SmartKey battery fails at 7 months
Thread Starter
Member
Joined: Apr 2014
Posts: 187
Likes: 3
From: Traverse City, Michigan
2023 AMG SL55,2015 S550 4MATIC, 2023 BMW X5
SmartKey battery fails at 7 months
My SmartKey battery expired sometime last night. Arrived home after a trip to Chicago, tried to open my doors in the airport parking garage and could not. The manual mini key worked fine and the car started ok inserting the key fob into the dash.
My car was built in July 2014. I was surprised that the key fob battery failed after only 7 months. My dealer replaced the battery as a courtesy for free (this time) and was surprised that it lasted as long as it did.
Is this what everyone else is experiencing? The dealership parts guy told me to buy the CR2025's in bulk blister packs & keep a spare in the glovebox.
Learn something new every day...
John.
My car was built in July 2014. I was surprised that the key fob battery failed after only 7 months. My dealer replaced the battery as a courtesy for free (this time) and was surprised that it lasted as long as it did.
Is this what everyone else is experiencing? The dealership parts guy told me to buy the CR2025's in bulk blister packs & keep a spare in the glovebox.
Learn something new every day...
John.
MBWorld Fanatic!
Joined: Feb 2010
Posts: 1,523
Likes: 394
'25 S63 AMG E Performance, '26 CLE 53 AMG
My SmartKey battery expired sometime last night. Arrived home after a trip to Chicago, tried to open my doors in the airport parking garage and could not. The manual mini key worked fine and the car started ok inserting the key fob into the dash.
My car was built in July 2014. I was surprised that the key fob battery failed after only 7 months. My dealer replaced the battery as a courtesy for free (this time) and was surprised that it lasted as long as it did.
Is this what everyone else is experiencing? The dealership parts guy told me to buy the CR2025's in bulk blister packs & keep a spare in the glovebox.
Learn something new every day...
John.
My car was built in July 2014. I was surprised that the key fob battery failed after only 7 months. My dealer replaced the battery as a courtesy for free (this time) and was surprised that it lasted as long as it did.
Is this what everyone else is experiencing? The dealership parts guy told me to buy the CR2025's in bulk blister packs & keep a spare in the glovebox.
Learn something new every day...
John.
Sure hope this is not something new for the w222. I have not replaced my battery yet in either of the key fobs. My '14 S550 4matic was built November 2013 and I have not had to replace my battery yet.
In fact, I purchased my 2008 S550 4matic in early 2008 and never replaced the battery in the key fob the entire time I had the car (sold it at time of picking up the 2014 S Class).
Additionally, my wife purchased her 2008 Acura MDX in November 2007 and we just replaced her battery in the key fob about 7 years later in December 2014.
You may have just had a bad battery.
Thread Starter
Member
Joined: Apr 2014
Posts: 187
Likes: 3
From: Traverse City, Michigan
2023 AMG SL55,2015 S550 4MATIC, 2023 BMW X5
Sure hope this is not something new for the w222. I have not replaced my battery yet in either of the key fobs. My '14 S550 4matic was built November 2013 and I have not had to replace my battery yet.
In fact, I purchased my 2008 S550 4matic in early 2008 and never replaced the battery in the key fob the entire time I had the car (sold it at time of picking up the 2014 S Class).
Additionally, my wife purchased her 2008 Acura MDX in November 2007 and we just replaced her battery in the key fob about 7 years later in December 2014.
You may have just had a bad battery.
In fact, I purchased my 2008 S550 4matic in early 2008 and never replaced the battery in the key fob the entire time I had the car (sold it at time of picking up the 2014 S Class).
Additionally, my wife purchased her 2008 Acura MDX in November 2007 and we just replaced her battery in the key fob about 7 years later in December 2014.
You may have just had a bad battery.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 1,938
Likes: 396
From: Iowa
2025 EQS580
A few days ago, I also had an issue with the smart key. I could not start the engine. Then it said on the screen "to start the engine by inserting the key fob into the dash after removing the pin. I did that and it started just fine. Since then however, the smart key has been working flawlessly. I'm not sure if that was a fluke the other day or the battery is indeed going dead.
MBWorld Fanatic!
Joined: Dec 2011
Posts: 4,379
Likes: 952
W212 FL
I have been using two key fobs just like a rotation of every two days and each approximately lasts 12-15 months maximum .
You can also try CR 2032 but I switched to a different brand , GP instead of Panasonic . Let's see how long they will go
You can also try CR 2032 but I switched to a different brand , GP instead of Panasonic . Let's see how long they will go
Thread Starter
Member
Joined: Apr 2014
Posts: 187
Likes: 3
From: Traverse City, Michigan
2023 AMG SL55,2015 S550 4MATIC, 2023 BMW X5
A few days ago, I also had an issue with the smart key. I could not start the engine. Then it said on the screen "to start the engine by inserting the key fob into the dash after removing the pin. I did that and it started just fine. Since then however, the smart key has been working flawlessly. I'm not sure if that was a fluke the other day or the battery is indeed going dead.
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Out Of Control!!
Joined: Jul 2003
Posts: 15,901
Likes: 4,632
From: North Scottsdale, AZ
'71 Pinto
In March 2014, a new feature was introduced. The KG function can be temporarily turned off by a double click (within 1 second) on the locking button of the key. The red LED will indicate the deactivation by two short and one long red LED flashing. The key does not need to be in close proximity to the vehicle in order for this feature to work.
IMO dealers should incorporate no cost key battery changes at each annual maintenance visit to avoid the need for customers to visit the dealership for key battery changes between maintenance visits.
IMO dealers should incorporate no cost key battery changes at each annual maintenance visit to avoid the need for customers to visit the dealership for key battery changes between maintenance visits.
Last edited by konigstiger; Feb 12, 2015 at 10:14 AM.
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Senior Member
Joined: Oct 2008
Posts: 420
Likes: 3
From: Houston, TX
2002 Mercedes S 430(GONE), 2001 E320(GONE), 2007 S550(GONE), 2009 BMW X6(GONE), 2014 S550
When i bought my 2014 the battery was already did, dealership replaced the battery, i was surprised too that battery lasted only year, never replaced battery in my 2007 since purchase
MBWorld Fanatic!
Joined: Feb 2014
Posts: 1,938
Likes: 396
From: Iowa
2025 EQS580
Well, this was very simple. Today I brought both smart keys to the dealer and within 2-3 minutes the service guy replaced both batteries at no cost. I was told that these batteries on the W222 don't last more than a year due to the fact that they control a lot more car features than the previous generation. In any case, since the dealer replaces the batteries at no cost to the customer and it only takes a couple minutes it's not a big deal at all.
Senior Member
Joined: Jul 2013
Posts: 308
Likes: 76
2024 E350
I have Keyless Go on my 2012 E-class and my battery usually lasts close to a year, but as the battery gets low I get a warning in the display each time I start the car saying that it's time to replace the key fob battery. Your cars don't give you a message like that?
Sometimes you can find a 2-pack of the batteries at Dollar Tree stores. I recently bought a 3-pack at Radio Shack's going out of business sale for 80 cents.
Sometimes you can find a 2-pack of the batteries at Dollar Tree stores. I recently bought a 3-pack at Radio Shack's going out of business sale for 80 cents.
Senior Member
Joined: Nov 2013
Posts: 263
Likes: 0
S 550
We have had our 2014 for 16 months and are still on the first set of batteries but we only have 7k miles on the car. So maybe our low mileage accounts for the battery lasting longer. I also wonder if some fobs might have the buttons being pushed while in pockets causing the battery to drain more quickly.
MBWorld Fanatic!
Joined: Dec 2011
Posts: 4,379
Likes: 952
W212 FL
I have been using two fobs in rotation and never felt that the buttons on the fobs are being pressed on while one fob is in my pocket or anywhere inside the door bins with or without this key fob case I am uploading for you to see
As a Keyless GO user you may need to buy one of these . I have only one case however .
As a Keyless GO user you may need to buy one of these . I have only one case however .
Super Member
Joined: Dec 2010
Posts: 831
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From: N.C. USA
2015, ML250 BlueTEC
How to save battery $$
Buy my key batteries on Amazon. Last time bought new Sony batteries dated ahead for 8 yrs, for .40 ea. Believe it was 20 batteries for $8. Price not always that good. But cheaper & easier than going to the MB dealer. Once you learn how to change battery you can do it in a minute.
