Sensor Function Using the Pressure Increase/Decrease method
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2004 GMC Yukon XL, 2004 GMC Yukon, 2004 Chevrolet Tahoe, 2004 Chevrolet Suburban, and 2004 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
Each sensor takes a pressure measurement sample once every 20 seconds while in stationary mode. If the tire pressure increases, or decreases by more than 11 kPa (1.6 psi) from the last pressure measurement, another measurement will occur immediately to verify the change in pressure. If a pressure change has indeed occurred, the sensor transmits re-measure mode transmission. When the PDM receives a re-measure mode transmission while in TPM learn mode, it will assign that sensor Id to the location on the vehicle relative to the order in which it was learned.