Tire pressure monitoring systems (TPMS) are now impossible to run from when buying a new vehicle. Every new vehicle made for sale in the USA has a TPM system as standard equipment. There are several exceptions though: the vehicle must have only four wheels (so no dual-wheeled trucks or motorcycles), and the GVWR must be less than 10,000lbs.
Audi has been keeping up with TPMS technology since 2002. Starting with the optional system on the A8’s and S8’s, they then threw the system on their whole line to comply with the recent law. They have used several valve sensors and we carry every sensor the Audi’s would use up to the 2009 model year.
The basics of the direct TPMS is that it uses a sensor in the wheel/tire to wirelessly relay pressure back to the driver on some sort of display. Some vehicles have a digital info screen that will show all four tire pressures (five pressures if spare has sensor) all the time. While others might just flash a low-tire-pressure light on the dash. There are also two different styles of sensors for this system: a valve sensor and a strap/band sensor. Only valve sensors are used by the direct system-equipped Audi’s, although if you bought an aftermarket SmarTire TPM system, those use the sensors held on by a strap around the barrel of the wheel.
Audi’s indirect system will not affect the choice of switching aftermarket wheels or tires. The system runs off of the ABS/wheel-speed sensors which “count” the number of revolutions of each tire. If the right-front tire is low (25psi) it will spin faster than the left-front tire (35psi), so the ABS system will recognize this change and alert the driver with a flashing light near the gauge cluster and possibly a loud chime. The 2009 Audi A6 has been equipped with a new generation of indirect system. This is the only vehicle running an indirect TPM system that complies with the US TPMS law.
Audi uses sensors produced by two different companies: Beru and Siemens. US-spec Audi’s use four different sensors so be wary of which sensor your vehicle needs. If you have any questions about the TPMS-fitment on a wheel that The Tire Rack sells, I can look up the wheel and confirm if it will work with your vehicle.
Audi has gone to a ABS-based system for all the new 2010 cars (except R8), so sensors are no longer needed. (see above for details of the system). While the system is not able to give information on precise PSI in each tire, it still gets the done without the expense and hassle of wireless transmitters !