jrpisha

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.

MTrauman

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.

jrpisha

Yeah, this was a first for me. Let's hope it was just a bad battery. The dealership's service guy's sarcasm didn't help...

sam9187

Forget the battery my entire key stopped working after 2 weeks. They had to order me a new key fob.

AppleFan1

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.

BenzV12

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

jrpisha

Bean, that's no fluke - that's typical of a SmartKey battery breathing it's last breath...

konigstiger

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.

Arlen777

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

AppleFan1

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.

jumpman726

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.

DaveVY

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.

BenzV12

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 .

greasykid

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.

akmatic63

Funny. I was in my dads car the other day, noticed the key fob battery should be replaced. About a year an a half/5k miles.

greasykid

Earlier cars like my 2005 E Class had 2 batteries in the fob. Now only 1. So batteries only last 1/2 has long now.