The tire pressure monitor system monitors the air pressure in all road tires and provides information to the driver if any road tire is moderately under-inflated or a warning to the driver when any road tire is significantly under-inflated. The tire pressure monitor system also provides information to the driver if any tire is over-inflated or if there is a large discrepancy between the air pressures of the left and right tires on a given axle. By using adaptive threshold values tire pressure monitor system can compensate for changed air pressure for various driving conditions, i.e. extra fill of air pressure for high-load, high-speed etc. The tire pressure monitor system also allows the driver to display the individual tire pressure and its locations on the driver information center display. The system uses four tire sensors, remote function receiver and the body control module (BCM). After any tire rotation or component replacement the tire pressure monitor system must be re-learned. Tire Pressure Indicator Sensor Learn

If all of the road wheels are without the tire pressure sensors, e.g, winter tires are installed, the system will recognize the change, enter into Winter Mode, and not show a malfunction.

Tire Pressure Monitor Sensor

The tire pressure monitor sensor, one in each wheel/tire assembly, sends sensor ID, tire temperature, tire pressure, tire rotation direction, and battery low level via radio frequency communication. When the vehicle is stationary, the sensors internal accelerometer is inactive, which puts the sensors into a stationary state. In this state the sensors sample tire pressure once every 30 s and do not transmit at all if the tire pressure does not change. As vehicle speed increases to above 20 km/h (15 MPH), centrifugal force activates the sensors internal accelerometer causing the sensors to go into rolling mode. In this mode, the sensors sample tire pressure and temperature once every 10 s and transmit in rolling mode once every 60 s. If an 8.3 kPa (1.2 PSI) change in tire pressure has been detected the sensor will transmit immediately.

If power is disconnected from the BCM or if the vehicle battery is disconnected each tire pressure sensor ID is retained but all of the tire pressure information is lost. Under these circumstances the BCM cannot assume that the tire pressures were maintained over an unknown period of time. If equipped, the driver information center will display all dashes and the scan tool will indicate a default tire pressure value of 1 020 kPa (148 PSI) for each tire. Driving the vehicle above 20 km/h (15 MPH) for at least 2 min. will activate the sensors causing the driver information center to display the current tire pressures.

The BCM has the ability to detect malfunctions within the tire pressure monitor system. In the event a DTC is set, the tire pressure monitor indicator icon on the instrument cluster will flash for 1 min. and then remain illuminated after the ignition is turned ON and the instrument cluster bulb check has been completed. Any malfunction detected will cause the driver information center to display a service tire monitor system type message.