why does my BMW 3 Series G20/G21 (2019-2024) airbag light stay on after starting

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, torx screwdriver
• Disconnect the negative battery terminal to prevent accidental airbag deployment.

2. Retrieve and Clear Error Codes

• Connect the OBD-II scanner to the vehicle's diagnostic port.
• Retrieve any stored error codes related to the airbag system.
• Clear the codes and check if the airbag light turns off; if it returns, proceed to further diagnostics.

3. Inspect and Repair Wiring and Connectors

• Inspect the wiring harness under the seats and around the airbag control module.
• Secure any loose connections or replace damaged connectors.
• If necessary, use a multimeter to check for continuity in the wiring.

4. Replace Faulty Components

• If specific fault codes indicate a faulty airbag sensor or control module:
  • Disconnect the battery again.
  • Remove the affected component using a socket set and torx screwdriver.
  • Install the new component and secure it properly.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the vehicle and check if the airbag light remains off.
• Conduct a brief test drive to ensure the airbag system operates correctly.