Future governmental regulations may call for new vehicles to have tire pressure
monitoring systems (TPMS) to warn of low tire pressure. As one of its safety initiatives,
Subaru already installs TPMS on these 2005 Outback models:
Other models will follow.
What TPMS Does
TPMS is intended to alert the driver if tire pressure in one or more tires falls below a preset value. A drop in tire pressure could result from:
Subaru TPMS is designed to illuminate a warning light if air pressure in any tire drops between 26 and 27 pounds per square inch (psi). When all tires are above a minimum pressure of 29 psi, the warning light is off.
Major Subaru TPMS components include:
How TPMS Works
The wheels’ air-pressure sensor/transmitter assemblies transmit individual air-pressure levels via radio signal to the receiver/control unit. Roll switches in the assemblies turn on the sensors when vehicle speed reaches between seven and 20 mph.
Transmitter data include detected air pressure, ID code and a code indicating the transmitter’s current mode. Each assembly’s sensor takes measurements every 30 seconds, which are transmitted every 60 seconds. After the vehicle has stopped for 15 minutes, the sensors enter sleep mode to conserve their batteries. They have life expectancies of 10 years or 100,000 miles.
The receiver/control unit collects data from the sensor/transmitter assemblies via a built-in antenna. If air pressure drops between 26 and 27 psi in one or more of the tires, the unit illuminates the warning light in the instrument panel (the system design does not indicate which tire is low).
TPMS – Important Safety Technology
Subaru equips vehicles with TPMS to improve safety. By warning of a tire’s air-pressure loss, TPMS helps drivers avoid accidents. An added benefit is the reduced wear and tear to a vehicle’s power train and chassis, potentially improving durability and lowering the cost of ownership.
(Don’t forget to check the air pressure in your tires at least once a month – especially after drastic fluctuations in ambient temperature. An investment in a quality tire gauge can save you money and improve safety!)