my BMW 3 Series G20/G21 (2019-2024) won't start, is it the battery or something else?

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, jumper cables, socket set.
• Disconnect the negative terminal of the battery to ensure safety while working on electrical components.

2. Battery Replacement (if necessary)

1. Remove the Battery

   • Unfasten the battery hold-down bracket using a socket set.
   • Disconnect the positive terminal first, followed by the negative terminal.
   • Carefully lift the battery out of the tray.

2. Install the New Battery

   • Place the new battery into the tray, ensuring it sits securely.
   • Connect the positive terminal first, followed by the negative terminal.
   • Secure the battery with the hold-down bracket and fasten it tightly.

3. Starter Motor Inspection (if battery is fine)

1. Access the Starter Motor

   • Raise the vehicle using a jack and secure it with jack stands.
   • Locate the starter motor, typically near the engine block.

2. Test the Starter Motor

   • Disconnect the electrical connector from the starter motor.
   • Use a multimeter to check for voltage at the starter motor when the ignition key is turned.
   • If there is voltage but the motor does not engage, replace the starter motor.
   • If there is no voltage, trace the wiring back to the ignition switch and check for faults.

4. Final Checks

• Reconnect the battery terminals and ensure all connections are tight.
• Close the hood and attempt to start the vehicle.