Tire Pressure Sensor
The Tire Pressure Monitoring System (TPMS) system uses 'active' tire pressure sensors which are mounted on each wheel rim, inside the tire cavity. The sensor is retained in position by the valve attachment to the wheel structure. The sensors transmit their Radio Frequency (RF) signals at 433 MHz.
The sensors periodically measure the pressure and temperature of the air inside the tire plus the centripetal acceleration acting on the sensor. These measurements are transmitted periodically to the RF receiver located behind the rear overhead console.
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 you replace the sensor, you must also replace the nut, seal and washer and tighten the sensor to the correct torque value as given in the Service Repair manual. For additional information, refer to: TIRE LOW PRESSURE SENSOR
The RF transmission from the sensor contains a unique identification code in its transmission data, so that the TPMS can identify the tire sensor on the vehicle. If you replace a sensor on a 'running' wheel, you need to program the identification for that sensor into the Tire Pressure Monitoring System Control Module (TPMSCM), using a Land Rover approved diagnostic system, otherwise the Tire Pressure Monitoring System (TPMS) will not monitor the wheel that is fitted with the sensor you replaced. The code is provided on a label with the complete wheel and tire assembly when new and is also printed on the casing of each sensor.
To conserve battery power, the tire 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 20 km/h (12.5 mph) to allow for slow driving.