Changing the battery in your Mercedes-Benz key fob is essential for maintaining vehicle access and functionality. A typical key fob battery lasts about 1-2 years, with 70% of key fob batteries needing replacement within 1 year due to heavy usage.
At A Glance
Whether you’re dealing with an older smartkey or a newer chrome smartkey, knowing how to replace the key fob battery will keep your Mercedes running smoothly. This guide will walk you through the process, using a CR2025 battery, and ensure your key fob works just as it should.
Key Takeaways:
- Use a CR2025 battery to replace the old one.
- Open the key fob using a flat tool or screwdriver.
- Ensure the battery is inserted with the positive side facing up.
- Test the fob after reassembly.
- Seek professional help if the fob doesn’t work after replacement.
Step-by-Step Guide To Changing The Battery In Your Mercedes Key Fob
The battery in your Mercedes key fob typically lasts between 1 to 2 years. After this time period, you must replace it. Various factors can cause the battery to drain more quickly, such as frequent use of the fob or extreme temperatures. You’ll notice that the key fob battery is dead when it fails to lock or unlock your car, or the signal strength becomes weak.
To replace, you’ll need a small flathead screwdriver, a replacement battery (typically a CR2025 or CR2032 lithium coin battery), and a clean, flat surface to work on. About 80% of Mercedes-Benz owners successfully change their key fob battery on their own, with the most common challenge being opening the fob without damaging it.
Step 1: Open The Mercedes Key Fob
”Remove the metal key by pressing the button. Find a notch along the fob’s edge. Insert a screwdriver to pry it open.”
To start, you’ll need to open the key fob to access the battery compartment. For newer chrome key models, a small flat tool, such as a coin or screwdriver, works best. Insert the tool into the seam of the fob and gently pry apart the two halves. For older smartkey designs, this may be slightly different, but the process remains straightforward.
Caution: The case may be tight; use a butter knife to open it. It may work out.
Step 2: Remove The Old Battery
Once you’ve opened the key fob, locate the battery compartment. If the fob uses a CR2025 battery, you should see it inside. Remove the old battery, which may be running low on power. When the battery is old, the key fob may have a weak signal or even a non-functioning panic alarm. Dispose of the old battery properly and prepare to install the new one.
Step 3: Insert The New Battery
- Place the new battery into the slot, ensuring it’s in the correct orientation (positive side facing up).
- Press it firmly into place.
Now, grab a fresh CR2025 battery commonly used in Mercedes key fobs. Ensure the battery is oriented correctly with the positive side (+) facing up. If you’re unsure of the battery’s orientation, the open slot in the compartment should help guide you. The biggest issue may be getting the orientation of the battery correct. You may have to redo it twice before it works. Ensure the new battery sits snugly in the compartment for optimal performance.
Step 4: Reassemble The Key Fob
- Align the two halves of the fob and snap them back together.
- Insert the metal key back into its slot.
After placing the new battery in the compartment, press the two halves of the key fob back together until they click. Be sure that the key fob is securely assembled. If your key fob has an emergency key or a circular panic button, verify that it functions properly after reassembly.
Step 5: Test The Key Fob
Test your key fob by locking or unlocking the vehicle once your key fob is back together. Press the panic alarm or use the key signal to ensure everything works smoothly. If the key fob still doesn’t work after the battery change, the issue could be with the charging system or the battery power supply.
Visit The Service Center If Needed
If your Mercedes-Benz key fob doesn’t work even after a battery replacement, it may need repairs. This could be a sign of a deeper issue, such as a problem with the charging system. You can visit your Mercedes-Benz service center to have the key fob or your vehicle checked for any issues. The finance center can also assist you in exploring options for newer models or certified pre-owned vehicles if a replacement is necessary.
Common Difficulties And Solutions
Although the process sounds straightforward, people face a few common issues when changing the battery in their Mercedes key fob.
- Fob Doesn’t Open: Some owners have reported difficulty opening their key fob due to the tightness of the casing.
Solution: Use a plastic pry tool if you’re worried about damaging the fob. These tools are gentler on the casing than a metal screwdriver and can help avoid scratches.
- Battery Doesn’t Fit: The replacement battery might occasionally not fit into the fob.
Solution: Double-check that you use the correct battery type (CR2025 or CR2032). If unsure, consult your vehicle’s manual or the fob’s original battery to confirm the size.
- Key Fob Still Doesn’t Work After Battery Replacement: Some users have reported that their key fob still doesn’t work, even after installing a new battery.
Solution: First, check to ensure the battery was installed correctly. If that’s not the issue, it’s possible that the fob needs to be reprogrammed. In that case, a visit to the dealership might be required for reprogramming.
Key Fob Care Tips
To prolong the life of your key fob battery, avoid dropping it or exposing it to extreme temperatures. If you experience frequent issues, it might be time to check the charging system, especially if you’re using a newer chrome smartkey model. Regularly checking the key fob battery can save you from future inconveniences.
If you’re having trouble or feel unsure about changing the battery, taking the key fob to a dealership or an auto shop for assistance is always an option. However, it’s a simple and rewarding DIY fix for most people.
FAQs
1.How Do I Know When My Mercedes Key Fob Battery Needs Replacing?
When your key fob’s signal weakens, the panic alarm doesn’t work, or you can’t unlock your car, it’s time to replace the key fob battery with a fresh CR2025 battery.
2.What Type Of Battery Does A Mercedes Key Fob Use?
Most Mercedes-Benz key fobs use a CR2025 battery. However, always verify your key type before purchasing a replacement, as older models may use a different type.
3.How Do I Open The Mercedes Key Fob To Change The Battery?
Use a small flat tool like a coin or screwdriver to gently pry open the Mercedes key fob. Be cautious not to damage the key holder or the panic alarm button.
4.Can I Change The Battery In My Mercedes Key Fob Myself?
Yes, you can change the battery yourself. Simply follow the steps to open the key fob, remove the old battery, and replace it with a CR2025. Ensure the battery is oriented correctly.
5.My Key Fob Battery Is Dead, How Do I Start My Car?
If your key fob battery is dead, unlock and start your vehicle with the emergency key. If issues persist, visit a service center for assistance with the charging system or key signal.
6.Why Is My Mercedes Key Fob Not Working After Changing The Battery?
If your key fob isn’t working after replacing the battery, the issue may lie in the charging system or the key signal. Take your vehicle to a Mercedes-Benz service center for further diagnosis.
7.How Often Should I Replace The Battery In My Mercedes Key Fob?
A Mercedes-Benz key fob battery generally lasts 1-2 years. Regularly check the battery and replace it when necessary to avoid losing access to your vehicle.
