I did this step from http://www.teamfc3s.org/info/articles/idle.html in my continuous quest to achieve a smooth and normal idle.

4. With the connector still removed, and the engine still off, place a 10k ohm, 1/4 watt resistor across the terminals of the connector. This is easy to do, simply insert the resistor leads into the connector. Make sure that the leads of the resistor do not short against each other or anything else. Turn the ignition on, without starting the car, and measure the AC voltage across the resistor. You should get a value between 6 and 7 volts after it settles down. A voltage lower than 5V indicates a likely ECU failure. Go here for more information. If you get the correct voltage, move on to the next step.

My S5 N/A got 10.7 volts warm and 9.4 cold. I'm thinking maybe my car just normally sends higher voltage than what they did article on. Does anyone know what the voltage is supposed to be?