What’s TPMS from Wikipedia?

A tire pressure monitoring system (TPMS) is an electronic system designed to monitor the air pressure inside the pneumatic tires on various types of vehicles. TPMS report real-time tire-pressure information to the driver of the vehicle, either via a gauge, a pictogram display, or a simple low-pressure warning light. TPMS can be divided into two different types — direct (dTPMS) and indirect (iTPMS). TPMS are provided both at an OEM (factory) level as well as an aftermarket solution. Find Autel TPMS at http://www.obd365.com/producttags/autel+tpms/ , and Autel MaxiTPMS® TS401is one of top sellers Autel TPMS.Direct TPMS

Direct TPMS employ pressure sensors on each tire, either internal or external. The sensors physically measure the tire pressure in each tire and report it to the vehicle’s instrument cluster or a corresponding monitor. Some units also measure and alert temperatures of the tire as well. These systems can identify under-inflation in any combination, be it one tire or all, simultaneously. Although the systems vary in transmitting options, many TPMS products (both OEM and aftermarket solutions) can display real time tire pressures at each location monitored whether the vehicle is moving or parked. There are many different solutions but all of them have to face the problems of exposure to tough environments and the majority are powered by batteries which limit their useful life. Some sensors utilise a wireless power system similar to that used in RFID tag reading which solves the problem of limited battery life by electromagnetic induction. This also increases the frequency of data transmission up to 40hz and reduces the sensor weight which can be important in motorsport applications. If the sensors are mounted on the outside of the wheel, which is the case for some aftermarket systems, they are in danger of mechanical damage, aggressive fluids and other substances as well as theft. If they are mounted on the inside of the rim, they are no longer easily accessible for service like battery change and additionally, the RF communication has to overcome the damping effects of the tire which additionally increases the need for energy.

A direct TPMS sensor consists of following main functions requiring only a few external components — e.g., battery, housing, PCB — to get the sensor module that is mounted to the valve stem inside the tire:
pressure sensor;
analog-digital converter;
microcontroller;
system controller;
oscillator;
radio frequency transmitter;
low frequency receiver, and
voltage regulator (battery management).

Most originally fitted dTPMS have the sensors mounted on the inside of the rims and the batteries are not exchangeable. With a battery change then meaning that the whole sensor will have to be replaced and the exchange being possible only with the tires dismounted, the lifetime of the battery becomes a crucial parameter. To save energy and prolong battery life, many dTPMS sensors hence do not transmit information when not rotating (which also keeps the spare tire from being monitored) or apply a complex and expensive two-way communication which enables an active wake-up of the sensor by the vehicle. For OEM auto dTPMS units to work properly, they need to recognize the sensor positions and have to ignore the signals from other vehicles’ sensors. There are hence numerous tools and procedures to make the dTPMS “learn” or “re-learn” this information, some of them can be carried out by the driver, others need to be done by the workshops or even require special electronic tools. The cost and variety of spare parts, procedures and tools has led to much trouble and confusion both for customers and workshops.

Aftermarket dTPMS units not only transmit while vehicles are moving or parked, but also provide users with numerous advanced monitoring options including data logging, remote monitoring options and more. They are available for all types of vehicles, from motorcycles to heavy equipment, and can monitor up to 64 tires at a time, which is important for the commercial vehicle markets. Many aftermarket dTPMS units do not require specialized tools to program or reset, making them much simpler to use.

Welcom to www.obd365.com to find your vehicle Autel TPMS.