How to Diagnose an Audi

1. Plug the code reader into your diagnostic port located underneath your Audi's steering wheel.
2. Insert your Audi's key into the ignition and turn it to the 'Accessories' position so that the car's electronics are activated.
3. Power on the code scan tool and allow it to scan for the diagnostic codes.
4. Write down the diagnostic codes as they appear on the screen.
5. Check the diagnostic codes that you received from the tool against a table of the diagnostic codes available for your car.