Your BMW key is a vital part of your vehicle, allowing you to lock and unlock the doors, start the engine, and access other features. If the battery in your BMW key is dead, you won’t be able to use it to operate your car. In this article, we’ll show you how to change the battery in your BMW key so that you can get back on the road as quickly as possible.
Before you begin, you’ll need to gather a few tools. You’ll need a small screwdriver, a new CR2032 battery, and a clean cloth. Once you have your tools, you can follow these steps to change the battery in your BMW key:
First, locate the small screw on the back of the key. Use the screwdriver to remove the screw. Once the screw is removed, you’ll be able to open the key housing. Be careful not to lose the small spring that is located inside the key housing. Next, remove the old battery from the key housing and insert the new battery. Make sure that the positive side of the battery is facing up. Finally, reassemble the key housing and tighten the screw.
Identifying the Key Type
Before proceeding with the battery replacement process, it is crucial to correctly identify the type of BMW key in your possession. BMW has employed various key designs over the years, each with distinct characteristics and battery requirements. Here’s a detailed guide to help you determine the key type and its corresponding battery specifications:
1. Traditional Key (Non-Remote)
BMWs produced before the late 1990s typically featured traditional keys without remote capabilities. These keys consist solely of a metal blade for manually unlocking the vehicle. They do not require batteries and therefore do not fall within the scope of this guide.
2. 3-Button Remote Key
Introduced in the late 1990s, 3-button remote keys became a common sight in BMWs. As the name suggests, these keys feature three buttons: lock, unlock, and trunk release. They are powered by a CR2025 battery, which is a small, round, lithium-ion battery.
3. 4-Button Remote Key
BMWs from the early 2000s onwards often came equipped with 4-button remote keys. These keys added a fourth button for activating the vehicle’s panic alarm. Like the 3-button key, the 4-button key also utilizes a CR2025 battery.
To summarize the battery requirements for different key types, refer to the table below:
| Key Type | Battery |
|---|---|
| Non-Remote Key | N/A |
| 3-Button Remote Key | CR2025 |
| 4-Button Remote Key | CR2025 |
Gathering Necessary Tools
Replacing the battery in your BMW key is a relatively simple task that can be done at home with a few basic tools. Before you begin, gather the following items:
**Tools**
- New CR2032 battery
- Small flat-head screwdriver or key
- Soft cloth
**Materials**
- Isopropyl alcohol (optional)
- Cotton swabs (optional)
| Tool/Material | Purpose |
|---|---|
| New CR2032 battery | Replacement battery for your BMW key |
| Small flat-head screwdriver or key | Used to pry open the key |
| Soft cloth | Protects the key from scratches during disassembly |
| Isopropyl alcohol (optional) | Cleans the battery contacts |
| Cotton swabs (optional) | Applies isopropyl alcohol to battery contacts |
Locating the Battery Compartment
Locating the battery compartment in a BMW key can vary depending on the specific model and year of the vehicle. However, the general steps are similar across most BMW key types:
- Locate the release button: Typically, there is a small button or lever on the back or side of the key that, when pressed or slid, will release the key blade.
- Remove the key blade: Once the release button is pressed, the key blade will slide out from the body of the key. Be careful not to lose the small spring that may be attached to the blade.
- Identify the battery compartment: With the key blade removed, you should see a small plastic cover or compartment on the back or bottom of the key body. This cover can be removed to access the battery.
- Remove the battery cover: The battery cover may be held in place by a small screw or a snap-fit mechanism. Using a small screwdriver or your fingernail, gently pry the cover loose and remove it.
| BMW Key Type | Battery Compartment Location |
|---|---|
| E46 Key (1999-2005) | Bottom of the key body, behind a removable plastic cover |
| E90 Key (2005-2012) | Back of the key body, under a hinged plastic cover |
| F10 Key (2010-2018) | Bottom of the key body, behind a snap-fit battery cover |
| G Series Key (2018-Present) | Back of the key body, under a hinged and latched cover |
Inserting the New Battery
1. **Locate the battery compartment.** The battery compartment is usually located on the back of the key fob. It is typically held in place by a small screw or latch.
2. **Remove the old battery.** Once you have located the battery compartment, carefully remove the old battery. Be sure to note the orientation of the battery so that you can insert the new battery in the correct direction.
3. **Clean the battery contacts.** Before inserting the new battery, clean the battery contacts with a cotton swab and rubbing alcohol. This will ensure that the new battery has a good connection.
4. **Insert the new battery.** Insert the new battery into the battery compartment, making sure that it is oriented correctly.
5. **Secure the battery compartment.** Once you have inserted the new battery, secure the battery compartment by tightening the screw or latch.
| Battery Type | Voltage |
|---|---|
| CR2032 | 3V |
| CR2025 | 3V |
6. **Test the key fob.** Once you have replaced the battery, test the key fob to make sure that it is working properly.
Proper Battery Orientation
Once you have the new battery, hold it so that the positive terminal (+) is facing up. In most cases, there will be a small arrow on the battery that indicates which side should face up. Now, align the battery with the terminals in the key fob, again making sure that the positive terminal on the battery aligns with the positive terminal on the key fob. The negative terminal on the battery should align with the negative terminal on the key fob.
Now, carefully insert the battery into the key fob, making sure that the terminals are properly aligned. Once the battery is inserted, the key fob should be able to close properly. If the key fob does not close properly, double-check that the battery is inserted correctly and that the terminals are properly aligned.
Step-by-Step Instructions:
1. Insert the key fob into the keyhole of the vehicle and turn it to the off position.
2. Press the key release button on the back of the key fob.
3. The key will now be released from the key fob.
4. Use a small flathead screwdriver or similar tool to pry open the back cover of the key fob.
5. Locate the battery and remove it by gently prying it out of its slot.
6. Insert the new battery into the key fob, making sure to align the positive and negative terminals correctly.
## Testing the Key Function
A simple test can often determine whether your BMW key battery needs replacing.
Hold the key close to your car door and press the lock or unlock button. If the doors lock or unlock, the key battery is likely still functional.
If the key does not work or has a limited range, the battery may be weak or dead and needs replacement.
Other signs that may indicate a weak or dead key battery include:
– Intermittent or delayed response when pressing the buttons
– Dim or flickering LED lights on the key
– Inability to start the car or open the trunk remotely
| Symptom | Possible Cause |
|---|---|
| Key does not work | Dead or weak battery |
| Limited range | Weak battery |
| Intermittent or delayed response | Weak battery |
| Dim or flickering LED lights | Weak battery |
| Inability to start the car or open the trunk remotely | Dead or weak battery |
If you suspect a weak or dead key battery, it’s best to replace it promptly to ensure uninterrupted access to your vehicle.
How to Change BMW Key Battery
Replacing the battery in a BMW key is a simple task that can be done in a few minutes. Here are the steps on how to do it:
Step 1: Locate the release button
The release button is usually located on the back of the key. Press the button and pull the key out of the casing.
Step 2: Remove the old battery
Use a small screwdriver or your fingernail to pry open the battery compartment. Remove the old battery and dispose of it properly.
Step 3: Insert the new battery
Insert the new battery into the compartment, making sure that the positive (+) side of the battery is facing up.
Step 4: Close the battery compartment
Put the cover back on the battery compartment and snap it into place.
Step 5: Test the key
Press any button on the key to test if it is working. If the key does not work, check the battery to make sure it is inserted correctly.
Troubleshooting Common Issues
The key does not work after replacing the battery
- Make sure that the battery is inserted correctly.
- Check the battery to make sure it is not dead.
- Clean the battery terminals with a cotton swab and rubbing alcohol.
- If the key still does not work, take it to a BMW dealer for further diagnosis.
The key works intermittently
- The battery may be low. Replace the battery with a new one.
- The key may be dirty. Clean the key with a cotton swab and rubbing alcohol.
- The key may be damaged. Take it to a BMW dealer for further diagnosis.
The keyfob is not recognized by the car
- Make sure that the keyfob is close to the car. It should be within 2-3 feet of the car to be recognized.
- Check the keyfob battery to make sure it is not dead.
- Try resyncing the keyfob to the car.
- If the keyfob still does not work, take it to a BMW dealer for further diagnosis.
| Battery type | BMW model |
|---|---|
| CR2025 | E36 |
| CR2032 | E46 E90 |
How To Change Bmw Key Battery
BMW key batteries typically last for several years, but they will eventually need to be replaced. The process of changing the battery is fairly simple and can be done in a few minutes.
Here are the steps on how to change the BMW key battery:
- Locate the small notch on the back of the key. Use a small screwdriver or key to pry open the case.
- Once the case is open, you will see the battery. Use a pair of tweezers to gently remove the battery.
- Insert the new battery into the key, making sure that the positive and negative terminals are aligned correctly.
- Close the case and snap it back into place.
- Test the key to make sure that it is working properly.
