Unlock Your BMW’s Hidden Feature: How to Open the Frunk with Your Key Fob

BMW key fobs are known for their convenience, offering remote access to various vehicle functions. While most owners are familiar with using their key fob to lock, unlock, and open the trunk, a lesser-known feature allows you to also open the “frunk” – the front trunk – on certain BMW models like the i3. This guide will show you how to unlock this hidden functionality and customize your BMW key fob to open the frunk, adding a new level of convenience to your vehicle access.

This customization involves making changes to your BMW’s coding, specifically within the Head Unit (HU_NBT) module. While it might sound complex, with the right tools and a little guidance, you can easily enable this feature yourself. This article is for informational purposes and, while based on successful user experiences, we always recommend proceeding with caution when modifying your vehicle’s settings.

Understanding the Possibility: Key Fob Frunk Access

By default, BMW key fobs are not programmed to open the frunk. The standard functions typically include:

• Locking and unlocking all doors
• Opening the rear trunk or tailgate
• Panic alarm

However, BMW’s iDrive system and vehicle control modules are highly customizable. Enthusiasts have discovered that by accessing specific coding parameters, it’s possible to remap one of the key fob buttons to control the frunk release. This is particularly useful for models like the BMW i3, where the frunk provides additional storage space.

Step-by-Step Guide: Coding Your Key Fob for Frunk Access

The following steps outline how to enable frunk opening via your BMW key fob. Please note: This guide is based on user reports and is intended for informational purposes. Modifying vehicle settings carries risks, and you should proceed at your own discretion. Incorrect coding can lead to unexpected behavior or even system malfunctions. If you are not comfortable with vehicle coding, it is highly recommended to consult a professional.

What You’ll Need:

• BimmerCode App (or similar coding software): BimmerCode is a popular and user-friendly app for iOS and Android devices that allows you to customize various BMW and MINI vehicle settings. Other coding software options may also work, but this guide focuses on BimmerCode due to its accessibility.
• OBD II Adapter: An OBD II adapter is required to connect your smartphone or tablet running BimmerCode to your BMW’s diagnostic port. Ensure the adapter is compatible with BimmerCode and your vehicle model.

Coding Process:

1. Connect to Your BMW:

   • Plug the OBD II adapter into your BMW’s OBD II port (usually located under the dashboard on the driver’s side).
   • Turn on your vehicle’s ignition (no need to start the engine, accessory mode is sufficient).
   • Launch the BimmerCode app on your smartphone or tablet and connect to your vehicle via the OBD II adapter. Follow the app’s instructions for establishing a connection.

2. Access the Headunit (HU_NBT) Module:

   • Once connected, BimmerCode will display a list of control units in your BMW.
   • Locate and select the “Headunit” or “HU_NBT” module. This module controls the iDrive system and related functions.
   • Choose “Expert Mode” within the Headunit module. Warning: Expert Mode allows direct access to coding parameters and should only be used if you understand the changes you are making. Incorrect modifications can cause issues.

3. Modify KEYCONF* Settings:

   • In Expert Mode, search for the following parameters: KEY_CONF_*. You will see a list of settings starting with this prefix, such as KEY_CONF_LOCK, KEY_CONF_UNLOCK, KEY_CONF_TRUNK, etc.
   • Change all of these KEY_CONF_* settings to aktiv (0x01). This enables the configuration options for each key fob button within the iDrive menu.

4. Change KEY_CONF_TAILGATE_SMALL_NAME:

   • Locate the parameter KEY_CONF_TAILGATE_SMALL_NAME. This setting likely controls the function associated with one of the key fob buttons related to trunk/tailgate operation.
   • Change the value of KEY_CONF_TAILGATE_SMALL_NAME to frontgate (0x03). This remaps the designated button function to “frontgate,” which in this context refers to the frunk or front compartment.

5. Verify in iDrive (Optional):

   • After coding, some users report that a new menu appears in the iDrive system, allowing you to customize the 3rd and 4th buttons on the key fob. This menu may be found under “Vehicle Settings” or “Doors/Locks.”
   • Within this menu, you should be able to select “Open front compartment” (or similar wording) as the action for one of the key fob buttons (likely button 3). Selecting this in iDrive is another way to confirm and activate the frunk opening function.

6. Test Your Key Fob:

   • Exit BimmerCode and disconnect the OBD II adapter.
   • Test your BMW key fob. Press the button you believe you have remapped (likely the 3rd button, often the trunk button) and see if it now opens the frunk. You may need to try both short and long presses of the button.

Important Considerations and Disclaimer

• Vehicle Compatibility: This guide is primarily based on experiences with the BMW i3. Compatibility with other BMW models may vary. Research or consult forums specific to your BMW model before attempting these coding changes.
• Software and Adapter Compatibility: Ensure that BimmerCode (or your chosen coding software) and your OBD II adapter are compatible with your specific BMW model and year.
• Warranty: Modifying vehicle software through coding may potentially void parts of your vehicle’s warranty. Be aware of this risk before proceeding.
• Risk of Incorrect Coding: Incorrect coding can lead to malfunctions or unexpected vehicle behavior. Double-check all settings before applying changes and proceed cautiously. If you are unsure about any step, seek professional assistance.
• Backup and Documentation: Before making any coding changes, it is always a good practice to back up your vehicle’s original coding settings within BimmerCode (if the app offers this feature). Document the changes you make so you can easily revert them if needed.

Conclusion

By following these steps, you can potentially unlock a hidden convenience feature in your BMW and customize your key fob to open the frunk. This modification can be particularly useful for BMW i3 owners, adding practicality to their vehicle’s storage capabilities. Remember to proceed with caution, understand the risks involved, and prioritize safety and responsible vehicle modification. Enjoy the added functionality of your customized BMW key fob!