Upgrade Your BMW E Series Key Fob to a G Series Style

Are you looking to modernize the feel of your BMW E series key fob? Many BMW owners appreciate the more modern design and enhanced functionality of the G series key fobs. If you’re one of them, you might be interested in upgrading your old E series key to the sleeker G series style. This guide outlines a DIY approach to perform this upgrade, enhancing both the look and potentially the performance of your key fob.

What You’ll Need for the Upgrade

To embark on this DIY Bmw Key Fob Upgrade, you’ll need a few key components and tools. The most crucial part is the G series key fob itself. For E series BMWs, specifically those with the CAS3 system, you need to ensure compatibility.

You can find a suitable key fob here: AliExpress Link to CAS3 Key Fob

KEYECU 315 / 868 MHz PCF7953 Chip CAS3 System Keyless-Go Function Upgraded Remote Key Fob for BMW 3/5series x5 x6 KR55WK491

Important Considerations Before Purchase:

• CAS3 Compatibility: Verify that the key fob explicitly states “CAS3”. Keys designed for CAS4 systems are not compatible and will not work with E series BMWs.
• Frequency: Confirm the correct frequency for your region. In the USA, 315 MHz is common. Check the back of your original E series key fob to verify the frequency.
• Comfort Access: This upgrade is designed for vehicles equipped with comfort access. The G series key fob does not physically fit into the ignition slot of E series models.

Besides the key fob, you will need some basic soldering equipment:

• Hot Air Station: A hot air station is essential for safely removing and re-soldering the microchip.
• Flux: Applying flux will aid in the soldering process and ensure clean connections.
• Tweezers: Precision tweezers are needed to handle the delicate microchip.
• Soldering Iron (Optional): May be helpful for touch-ups, but the hot air station is the primary tool.
• Kapton Tape: Heat-resistant Kapton tape to protect surrounding components during soldering.

Step-by-Step Guide to Upgrading Your BMW Key Fob

Disclaimer: This is a DIY modification that requires soldering skills and carries risks. Proceed at your own risk. Damage to your key fob or vehicle electronics is possible if not done correctly.

1. Prepare Your Workspace: Work in a well-lit area with ample space. Ground yourself to prevent static discharge.

2. Disassemble Both Key Fobs: Carefully open both your original E series key fob and the new G series key fob. You’ll need to access the circuit boards of both.

3. Locate and Protect the Chip: Identify the PCF7953 chip on both circuit boards. On the E series board, carefully apply Kapton tape to cover surrounding components, buttons, and any ICs to protect them from heat.

4. Remove the Chip from the E Series Board: Apply flux to the pins of the PCF7953 chip on the E series circuit board. Using the hot air station set to approximately 350°C (adjust based on your equipment and experience), gently heat the chip pins while lightly lifting with tweezers. The chip should detach once the solder melts.

5. Prepare the G Series Board: Apply flux to the landing pads on the G series circuit board where you will solder the chip.

6. Solder the Chip onto the G Series Board: Carefully align the PCF7953 chip onto the landing pads of the G series board. Use the hot air station to heat the pins and solder the chip in place. Ensure all pins are properly soldered for a good connection.

7. Reassemble the G Series Key Fob: Once the chip is soldered and cooled, carefully reassemble the G series key fob.

8. Test the Key Fob: Test all functions of your upgraded key fob, including comfort access, remote locking/unlocking, and range.

Important Notes and Considerations

• Button Sensitivity: Be cautious with heat exposure to the buttons during soldering. Excessive heat can damage them, making them less “clicky”. If this happens, consider sourcing replacement buttons from a donor board.
• Key Blade: The G series key blade is different from the E series blade. You will need to get the G series key blade cut to match your car’s key profile. Some users have reported issues with the G series blade being thinner, potentially causing issues with locking. You may need to experiment or consult a locksmith for key blade solutions.
• DIY Risk: This upgrade involves delicate soldering work. If you are not comfortable with electronics soldering, it is advisable to seek professional help or consider alternative options.

Alternative Options: Locksmith Programming

If the DIY approach seems too daunting, you might explore professional services. Some locksmiths specializing in automotive keys may be able to program a CAS3 G series key fob to your E series BMW. However, compatibility and success are not guaranteed, and it’s best to inquire with a locksmith experienced in BMW key programming.

Conclusion

Upgrading your BMW E series key fob to a G series style offers a modern aesthetic and potentially improved range and comfort access functionality. While the DIY method is achievable for those with soldering skills, it’s crucial to proceed with caution and be aware of the potential risks. By carefully following these steps and considerations, you can potentially enjoy the benefits of a G series key fob with your E series BMW.