Tire Pressure Monitoring System Sensor
The Tire Pressure Monitoring System (TPMS) uses active TPMS sensors which are mounted on each wheel rim, inside the tire cavity. The TPMS sensor is retained in position by the valve attachment to the wheel structure. The TPMS sensors transmit their Radio Frequency (RF) signals at 433 MHz.
The TPMS sensors periodically measure the pressure and temperature of the air inside the tire along with the centripetal acceleration acting on the TPMS sensor.
The tire pressure sensors are self-contained units as they do not have any electrical connections going into or coming out of the sensor.
If the TPMS sensor is replaced, the nut, seal and washer must also be replaced and the TPMS sensor tightened to the correct torque value. The correct torque value is given in the service repair information.
The RF transmission from the TPMS sensor contains a unique identification code in its transmission data. The TPMSCM can identify the TPMS sensor on the vehicle using the identification code.
When replacing a TPMS sensor on a running wheel, the identification for that TPMS sensor must be programed into the Tire Pressure Monitoring System Control Module (TPMSCM). The programing must be completed using the Jaguar Land Rover (JLR) approved diagnostic equipment. Otherwise the TPMS will not monitor the wheel that is equipped with the TPMS sensor that has been replaced. The code is provided on a label with the complete wheel and tire assembly when new. The code is also printed on the casing of each TPMS sensor.
If the TPMS sensor identification is not programed in, a warning indicator will appear on the Instrument Cluster (IC). The warning indicator illuminates on the IC until the TPMS has learned the new TPMS sensor identification, and localized to the correct wheel. This localization requires a 10 minute continuous drive above 20 km/h (15 mph). The TPMS system will not disable the warning indicator until the localization has occurred.
To conserve startup battery power, the TPMS sensor uses different transmission rates when the wheel is stationary or moving. The wheel speed required to change between the stationary and moving transmission rates is very low to allow for slow driving.