How to Replace the Battery in a 2001 Mercedes-Benz C240 Key Fob

If your Mercedes-Benz key isn't working perfectly, the battery more likely needs to be replaced. Below, we are going to tell you how to open Mercedes-Benz remote key fob and change a dead or weak battery DIY. If you decide to do it at home near C240, use this instruction, but first make sure you have all you need before you start.
What type battery key fob require
Before starting open key fob make sure that you have all recommended tools and materials: 2xCR2025 batteries and flat head screwdriver.- 2xCR2025 batteries
- flat head screwdriver
Simple steps to replace the battery in your car's key fob
Inside of your keyless entry remote installed button battery. Remove any internal key before you try to pry apart the key fob.
Carefully try to open your keyless entry remote with pry tools. Change CR2025 batteries with flat head screwdriver.
Now it's time to install new batteries inside fob’s body. Battery must be installed with the same polarity as was a previous. Your keyless entry remote will not work if you mistakenly place battery wrong way.
After the new batteries installed, check keyless entry remote by pressing buttons. If all functions works, assemble your fob’s body in reverse order.
The last thing to do is put your cover back on fob. Accurately try to assemble the pieces in place by hands from top to bottom. If your key body firmly closed, we done. If not, repeat the last step.
How to change the battery video guide
Mercedes Benz Key Fob Case Change and Battery Replacement Remote
Still not working? Buy new one