Tire Pressure Monitoring System (TPMS)
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The optional tire pressure monitoring system (TPMS) has the ability to monitor the air pressure of the four road tires. The tire-mounted pressure sensors transmit signals to the TPMS module by using the valve stem as an antenna. These transmissions are sent approximately every 30 seconds when the vehicle speed exceeds 32 km/h (20 mph). The TPMS module compares each tire pressure sensor transmission against two pressure limits - low and high. If the TPMS module determines that the tire pressure has exceeded the low or high limit, the TPMS module communicates on the SCP network to the vehicle message center, which then displays a warning message.