Tire Pressure Monitoring (TPM) - Operation

OPERATION

The Tire Pressure Monitoring (TPM) system uses radio and sensor technology to monitor tire air pressure levels. Sensors, mounted to each road wheel as part of the valve stem, transmit an RF signal indicating their individual pressure to a receiver located in the Wireless Control Module (WCM), commonly referred to as the Sentry Key Remote Entry Module (SKREEM). These transmissions occur approximately once every minute at speeds over 15 mph (24 km/h). The Tire Pressure Monitoring 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 15 mph (24 km/h). Once the wheels stop rotating for a period of approximately 20 minutes, the sensors shut down until again awaken. 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. Sensors will also transmit when a pressure change of one psi (seven kPa) or more is detected during that period. For more information on sensors, Operation.

If equipped with the premium TPM system, transponders located in three of the four wheel wells of the vehicle are used to provide the WCM with the location of the tire pressure sensors on the vehicle. The transponders are located in the left front, right front and left rear wheel wells. A fourth transponder is not necessary in the remaining wheel well due to the process-of-elimination theory. Once the system knows the location of the first three sensors it assumes the location of the fourth tire pressure sensor is in the remaining tire. For more information, Operation.

If the system detects that the tire pressure in any road tire is going low, beyond the Low Pressure (lamp) ON threshold (see following table), the TPM system will continuously illuminate an indicator lamp. Also, if equipped with the premium TPM system, a message will be displayed in the instrument cluster. The text message will indicate which tire is low and the display will show all current tire pressures, the low tire will be flashing with its pressure value. This message will be displayed for the rest of the ignition cycle, or until the Low Tire pressure condition has been corrected. A chime will sound upon initial detection. Once pressure in the suspect tire raises above the Low Pressure (lamp) OFF Threshold, the lamp will go out and the system returns to normal within approximately two minutes time. If a message center button is pressed, the message is replaced by the new message requested; however, if the Low Tire condition has not been corrected, the Low Tire pressure message will again be displayed.

If a system fault is detected, the indicator lamp will flash on/off for 60 seconds, once every 10 minutes.

For further information, refer to the Appropriate Diagnostic Information.

TPM THRESHOLD PRESSURES

NOTE: To determine the pressure thresholds for a vehicle, refer to the Tire Inflation Pressure (Placard) Label found on the Driver's B-Pillar, then apply the placard pressure to the following table.