The TPMS-4WD/6 Sensor is a realtime Tyre Pressure (and temperature) Monitoring System (TPMS). “Realtime” meaning the actual temperature and pressure at that moment in time. The system is designed to constantly monitor vehicle tyre pressure and temperature whenever the display unit is powered up. The kit consists of a display unit, 4 sensors, a power cord, a cigarette lighter adaptor and an integrated dual wire antenna.

Since the display unit consumes very little power, it is recommended that the display unit be hardwired to the vehicle’s 12V electrical system. The 12V supply should be live irrespective of the position of the ignition key switch. This will enable the TPMS-4WD to monitor the tyres not only when the vehicle is being driven, but also when it is parked.

The TPMS-4WD is designed to monitor 4 wheels and hence is designed for 4 wheel vehicles only. The kit is supplied with 4 sensor assemblies which need to be fitted to each wheel of the vehicle. Each of the sensors consists of a valve stem, incorporating the new tyre valve and an electronic assembly which is encapsulated within a plastic/silicon housing.

The actual electronics within the sensor consist of a low power 433.92Mhz RF transmitter, a microprocessor with embedded temperature and pressure transducers, a motion detector and a lithium battery as a power source. None of the electronic components, including the lithium battery are serviceable or replaceable. In the event of a failure the whole valve sensor assembly can be replaced.

The sensors need to be fitted in place of the existing tyre valves. To do this the tyre needs to be removed from the rim, the sensor fitted and then the tyre re-fitted. Normally this work is carried out most efficiently by a specialised tyre fitter or tyre retail outlet. Only rims with a tyre valve mounting hole of 11.3mm are supported. This is the standard size for most OEM and after market rims.

The battery life of the sensors has been designed to last for 7 years (typical) or 250,000km of driving. The concept being that if a set of sensors is fitted to a vehicle at the time that a new set of tyres are fitted, the sensors will outlast the life of the tyres. As that set of tyres is replaced, it can then be determined whether the sensors should be replaced or whether they can be utilised for another tyre cycle.

The valve stem section of the sensor assembly is manufactured from high grade aluminium with a propriety finish to prevent corrosion. Aluminium is utilised to ensure the sensor assembly weight is kept to a minimum, while at the same time providing mechanical strength essential for 4WD applications. This low weight ensures that wheel balancing can be easily achieved. Under certain environmental conditions electrolysis can occur if a steal valve cap is fitted to the valve stem. This electrolysis will cause the valves stem to corrode. As a result it is recommended that only the supplied plastic or an aftermarket aluminium valve cap be used.

The encapsulated electronics will ensure reliable operation even in dirty, muddy and humid off road environments. In addition the encapsulation will also ensure the sensor can withstand heavy vibration and shock typically encountered on rough 4wd tracks. As all the electronics are environmentally and mechanically insulated and isolated, including the lithium battery, the unit is not serviceable in any way, nor can the battery by replaced.

Additional sensors can be purchased and fitted to spare tyres, however only 4 wheels can be monitored at any one time. Tyres can be easily rotated along with spare tyres due to  patented sensor ID technology.