how to address B1221 code in my Volkswagen Golf Eighth Generation (2020-present)?

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, cleaning solution, battery terminal cleaner, and a replacement battery if required.
• Ensure the vehicle is parked on a level surface and the engine is off.

2. Battery Terminal Inspection

• Disconnect the negative terminal first, followed by the positive terminal.
• Clean any corrosion using a battery terminal cleaner and a wire brush.
• Reconnect the positive terminal first, followed by the negative terminal.

3. Battery Testing

• If the battery voltage is low (below 12.4 volts), charge the battery using a battery charger.
• If the battery holds a charge poorly, replace it with a new battery that meets the manufacturer's specifications.

4. Alternator Inspection

• Check the alternator connections and ensure they are secure.
• Start the engine and measure the voltage at the battery terminals with a multimeter; it should read between 13.7 to 14.7 volts.
• If the alternator is not charging properly, consider replacing it.

5. Clear Codes and Test

• Use the OBD-II scanner to clear the B1221 code and any related codes.
• Test drive the vehicle for a short distance to check if the code returns and to ensure all electrical systems function correctly.