If a "low tire pressure" warning light is observed, filling the tire(s) to specified pressures should shut the light off. If the light remains on, follow the below procedure.
In order for the tire pressure monitoring system to work, the specified pressures must be re-saved each time a wheel is changed.
You must perform the following steps in order for the system to function properly:
Check and correct the pressures in all the vehicles's tires (including the spare) to conform to the information provided on the tire pressure label. The label is located on the inside of the fuel filler flap.

Turn on the ignition.
Press the "Menu" button to open the start menu.

Move the selection arrow to "Set" by rotating the turn/push knob.

Press the turn/push knob. The settings menu appears.
Move the selection arrow to "Tire pressure" by rotating the turn/push knob.
Press the turn/push knob. The submenu "Tire pressure" appears.
Move the selection arrow to "Store pressures!".
Press the turn/push knob. A check mark appears. The system reports that the store request was saved with "The current tire pressure will be saved."
Move the selection arrow to back.
Press the turn/push knob to leave the tire pressure menu.
When "Store pressure!" is initiated the system automatically starts the learning procedure.
The "Store pressures!" procedure must be launched after every change in air pressure and after every wheel change. The system does not know the specification pressure until the procedure is complete so that it can report a loss of pressure.
After the specification pressures are stored, the learning procedure starts.
The learning procedure is launched by storing the air pressures. It is completely automatic and normally you never notice it. It takes several minutes while you are driving.
The system will learn the tire pressures set on the vehicle and will check to see if any tires were changed.
During this learning phase, the system will be operable, but it will only issue a warning when the pressure in one or more tires (including the spare) deviates from the specified pressures by more the 6 psi (0.4 bar).
If this still does not fix the problem, contact your authorized Audi dealer for assistance.
If a "low tire pressure" warning light is observed, filling the tire(s) to specified pressures should shut the light off. If the light remains on follow the below procedure.
The tire pressure monitoring system is operated using the Multi Media Interface (MMI). The system monitors tire pressures that are specified by the operator. Before hand, the following steps must be performed:
First check and correct all tire pressures on vehicle (including spare tire) Refer to specified tire pressures on tank flap data label.
After checking the tire pressures and correctly filling the tires, the current pressures must be stored in memory. The system automatically carries out an adaptation procedure.
Proceed as follows:
Switch ignition on.
Press function key "CAR".
In"CAR" menu, select systems.
Select tire pressure monitoring system.
Select "store tire pressure".
Tire pressures must be stored each time the tire pressure and or tire has been changed.
Further information can be found under "Wheels and Tires : Tire Monitoring System : Service and Repair : Procedures.
Audi utilizes a sophisticated computer system to monitor tire pressure. If a low tire pressure warning light is observed, simply filling the tire(s) to specified pressures should shut the light off. If this does not shut off the light, then follow the "changing a wheel" initialization procedure.
When you change a wheel, the new tire must be initialized.
Press the "CAR" function button.
Select Systems in the CAR menu.
Select Tire pressure monitoring.
Select Initialize wheels.
When you change a tire, you must perform the Initialize wheels procedure. You must do this each time to change a tire. The procedure can take up to 20 minutes. During this time, the tire pressure and temperature will not be displayed because the sensors are being "broken in" and the learning process is taking place.
During the learning process the tire pressure monitoring system is only partially available It only warns when tire pressure drops below the minimum permissible specified pressure. This can indicate one or more tires as well as the spare tire. If this is the case, the warning symbol appears together with the message Tire pressure!
If this still does not fix the problem, contact your authorized Audi dealer for assistance.
Audi utilizes a sophisticated computer system to monitor tire pressure. If a low tire pressure warning light is observed, simply filling the tire(s) to specified pressures should shut the light off. If this does not shut off the light, then follow the "changing a wheel" initialization procedure.
When you change a wheel the new tire must be initialized.
Select Wheel change in the Tire pressure menu.

Your tire change is incomplete if you do not access the Driver Information System menu and select and confirm Wheel change. You must do this each time to change a tire. The procedure can take up to 20 minutes. During this time, the sensors are readjusting to the new wheel/tire combination and the monitoring system is operating at reduced sensitivity. It only warns when tire pressure drops below the minimum permissible specified pressure. If this is the case, the warning symbol appears together with the message Tire pressure!

During the learning phase, the tire pressure monitoring system performs only is only partially available. It only warns when tire pressure drops below the minimum permissible specified pressure.
If this still does not fix the problem, contact your authorized Audi dealer for assistance.