Tire Pressure Monitor System (TPMS)

The Tire Pressure Monitor System (TPMS) monitors pressure in each road tire. Temporary spare wheels are not fitted with tire pressure sensors, therefore the spare tire is not monitored. To do this, the system uses a TPMS module, TPMS RF receiver, 4 initiators, instrument cluster, a 4 TPMS sensors and a data circuit to perform system functions.

The TPMS module uses the 4 initiators (located in each wheelhousing) and the TPMS RF receiver (mounted near gear shifter) to detect when a tire pressure is below the recommended tolerance, locate the position of the tire on the vehicle, and cause the instrument cluster to display appropriate warnings and/or indicate the status/failure of tire pressure monitoring system components. The TPMS module can automatically learn the position of tires on the vehicle if the tire pressure sensors or their positions are changed on the vehicle. This process is performed by using the Auto-Location function, which requires the vehicle to be driven at 16 mph (25 km/h) or more for 15 minutes.

If the system detects a deflation, the instrument cluster will display the tire pressure warning indicator and an appropriate message will be displayed in the message center.

The TPM system enters "Parking Mode" when the vehicle speed has been less than 16 mph (25 km/h) for 15 minutes. In this mode, the sensors will transmit once every 13 hours. If there is a decrease of 1 psi (7 kPa) or more in the tire pressure, the sensors will transmit more often. When the vehicle speed increases to 16 mph (25 km/h) or more, the TPM system enters "Driving Mode". In this mode, the tire pressure sensors will measure the pressure and temperature of each tire every 15 seconds once, then once every 60 seconds. If a change in tire pressure is sensed, the sensors will transmit more often. Pressure and temperature measurements are transmitted periodically to the external RF receiver on the vehicle. To conserve battery power, the sensor transmits at different rates when the wheel is stationary or moving.