How to Open Your 2009 Mercedes-Benz C300 Key Fob & Change Battery

How to Open Your 2009 Mercedes-Benz C300 Key Fob & Change Battery

If your auto keyless entry remote is no longer open doors perfectly, the cell battery surely must to be changed. In this post, we described how to disassembly your keyless entry remote and change your Mercedes-Benz key battery.

What kind of battery remote key fob use

Before going to disassembly remote key fob check all that you need: flat head screwdriver and CR2025 batteries.
  • 2xCR2025 batteries
  • flat head screwdriver

Simple steps to change the battery in your C300's keyless entry remote

Inside of your keyless entry remote installed button cell battery. Move the key out of the way if it is in the remote key fob.

Accurately try to open your keyless entry remote with pry tools. Replace CR2025 batteries with flat head screwdriver.

Now it's time to install new batteries inside fob’s case. Battery must be installed with the same polarity as was an old. Your keyless entry remote will not work if you by mistake place battery wrong way.

Before assembling keyless entry fob's case, make sure that all is functioning by pressing buttons on remote key fob.

The last thing to do is put your cover back on fob. Delicately try to put the pieces together by hands from top to bottom. Check your remote key fob shell for gaps. If it is not tightly closed try to repeat last step.

Video of remote key fob opening

Mercedes C300 (W204) SmartKey Battery Replacement (Smart Key)

Still not working? Buy new one


Remote key fob of Mercedes-Benz C300 require 2xCR2025 batteries. Most CR2025 batteries are under $4-6 build upon the size packaging, type and brand you buy. Take your old battery to the store, with you to find a proper replacement.

Usually, after remote key fob battery replace, you do not need to reprogram. Keyless entry remote reprogramming procedure often described in user's manual of your vehicle.

Changing your keyless entry remote battery is easy to do in 2009 Mercedes-Benz C300. Most of car manufacturers think about clients and make a special hole for key fob disassembly.

Car service price for replace the battery in key fob is from 50 to 600 dollars depending on the brand.

Key fob batteries in Mercedes-Benz C300 should be replaced every 3-4 years, also this will vary based on frequency of use and battery quality. If your remote key fob decreased signal strength, you should change batteries before it stop working and make trouble for you.

If your auto has low key battery indicator on dashboard, signal strength reduced, need multiple clicks to unlock or lock doors or fob's battery more than 4 years old, in most cases battery change inside keyless entry remote needed. Installed battery is dead with a high probability, but if it's not fix problem, fob replace or repair required.
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Fob Compatibility:

  1. FCC ID: KR55WK49031
  2. Models: 2006-2009 Mercedes-Benz C300