How do I reset the electronic control unit (ECU) in my Audi A2?

My Audi A2 seems to be experiencing electronic issues and I've been advised to try resetting the ECU. How exactly do I do that?

To reset the ECU in an Audi A2, disconnect the negative terminal of the battery for at least 30 minutes, then reconnect it and start the car.

Before resetting the ECU, make sure to check for any error codes or warning lights using an OBD-II scanner. This can give you a better idea of the underlying issue.