To code new features into a 2017 BMW 3 Series using a diagnostic tool, you should follow a structured process. Here's a detailed guide:

Step 1: Obtain the Necessary Equipment

• Acquire a compatible diagnostic tool or coding device such as BMW ENET cable, K+DCAN cable, or a high-end tool like the BMW ICOM.
• Ensure you have a laptop with stable internet access and sufficient battery life.
• Download necessary software such as ESYS, ISTA/P, or BimmerCode, depending on the type of coding you plan to perform.

Step 2: Prepare Your Vehicle

• Ensure your BMW 3 Series has a full battery charge or connect it to a battery maintainer to prevent any power loss during the coding process.
• Turn off unnecessary electric devices within the car to conserve battery power.
• Find and identify the car's OBD-II port, usually located under the dashboard on the driver's side.

Step 3: Connect Your Diagnostic Tool

• Plug the diagnostic tool into the car’s OBD-II port. Connect the other end to your laptop.
• Initiate the installed software and set it up for communication with the vehicle.

Step 4: Backup Existing Configurations

• Before making any changes, use the software to create a backup of the car’s current configuration settings. This is crucial in case your coding efforts need to be reverted.
• Save these backup files securely on your laptop.

Step 5: Select and Code New Features

• Navigate through the software to select the specific modules you want to code. These include modules such as the Body Domain Controller (BDC), Car Information Computer (CIC), or Dynamic Stability Control (DSC).
• Adjust the settings for the desired new features, such as activating digital speedometer display, enabling remote windows control, or modifying daytime running light behavior.
• Certain software options like BimmerCode might offer a simple interface with toggle switches, while others like ESYS could require you to input specific codes.

Step 6: Save and Verify Changes

• After making the desired adjustments, apply and save the changes through the software.
• Reboot the Car Information Computer (CIC). This can usually be done by turning the ignition off and then on again, or through the software instruction.
• Verify that the new features are working by testing them in the car. Check functionalities to ensure the coding has been successful.

Step 7: Troubleshoot (if necessary)

• If the features do not work as expected, refer to your backup and restore the original settings.
• Review any error messages in the diagnostic software, as they may provide clues on what went wrong. Iterate over the process as needed.

By carefully following these steps, you can code new features into your 2017 BMW 3 Series effectively and safely.