Tire Pressure Monitor (TPM) System

The Tire Pressure Monitoring (TPM) system monitors air pressure in the four road tires (excludes spare). Pressure in the spare tire is not monitored. There are two tire pressure monitoring systems available, a base system and a premium system. The base system does not specify how many tires are low or where they are located. The premium system does so.

The sensor will broadcast this information, along with a unique 32-bit ID, to a central receiver circuit located inside the Wireless Control Module (WCM). On premium models, sensor transponders are mounted in wheelhousings (2 in front, and one in rear). If a warning or fault condition exists, the WCM will send a bus message request to illuminate the low pressure warning light and to sound a chime. On some models, instrument cluster will display warning messages.

The TPM system remains active even if no tire pressure related message is displayed. The sensors lay dormant (Park Mode), then wake and start transmitting (Drive Mode) when the vehicle first reaches speeds over 20 MPH (32 KM/H) for 2006 models and 15 MPH (24 KM/H) for 2007 and later models. Once the wheels stop rotating for a period of approximately 20 minutes, the sensors shut down until again awakened. Although not transmitting as when in Drive Mode, while in Park Mode, the sensors still transmit approximately once every 13 hours to let the receiver know air pressure status at that time.