How to reset the tire pressure monitoring system in an Audi A4?

I recently purchased a used Audi A4 and the tire pressure monitoring system keeps showing an error. How can I reset it?

First, check the tire pressure in all four tires using a gauge. If they are not within the recommended range, fill them up with air. Then, press and hold the 'Car' and 'Menu' buttons on the MMI panel at the same time. Select 'Reset' and then 'Tire Pressure Monitor'. Follow the prompts to reset the system.

Another option is to drive your Audi at a speed of at least 20 mph for at least 10 minutes. This will allow the system to recalibrate itself and reset the error. However, if the error persists, you may need to take your car to a mechanic to have the system checked.