Type of TPMS Valves
The types of TPMS:
There are two types of sensors; the indirect TPMS, and the direct TPMS.
This type of pressure monitoring system is linked to the ABS system of the car to evaluate an approximative pressure in the tires. This principle is based on the fact that if a tire has a flat or a leak, its overall diameter will be smaller, making its speed decreasing compared to the correctly inflated tires of the car. Since they cannot give some accurate data in real time and they rely on the pressure of one tire compared to the other, those sensors are considered indirect TPMS. It is the on-board computer who is evaluating if a tire is deflated, and the warns the driver.
Once a tire is being inflated correctly after a deflation, it takes about 20 to 60 minutes of driving before the computer relearns the new parameters of the sensors.
Direct sensors are able to measure the axact pressure in each and every tire because of individual sensors placed directly in the four tires. As opposed to the indirect TPMS, they can have a precise value on not only the tire pressure, but also the temperature inside, to prevent over-heating. As soon as there is something irregular, the information is transmitted to the driver through the car’s computer.
Because the direct TPMSs are separated from the computer or the car, they can work with batteries or by a system of electromagnetic induction creating electricity, solving the battery short life. When using induction, the TPMS can generate faster delays for information at decrease the weight of the sensors. This being said, since they are located ouside they vehicle, they are more vulnerable to be broken by a big imlact, leading to the deprogramming of the sensor if the impact is too important.
Original and Universal Sensors
Those sensors are preprogrammed with the specific parameters of the car they were made for. They do not require any additional tools to be linked with the car, which makes it harder for garages. If they wanted to provide some to their customers, they would need to store many different types of TPMS for all the manufacturers, by sets of four. Happily, the majority of the sensors are aftermarket universal TPMS, whioch can be programmed for almost any vehicle.
As mentioned above, universal sensors are all the same; same shape, going at the same place, and are all programmed the same way. They are offered in two different versions, 433 Mhz or 315 Mhz, depending on what frequency the car is using. Basically, universal sensors TPMS are sensors connected to standard valves.
Before the installer gets the tire mounted on the wheel, he programs the TPMS by a machine by entering the vehicle information on which they will be installed. Once the sensors are pre-programmed, they are ready to be linked to the vehicle. However, universal TPMS need a special programming tool which is going to make the link between the car and the sensors themselves.
It allows the on-board computer to ‘understand’ the new codes generated by the TPMS newly programmed.
At PMCtire, we are using ITM universal TPMS, which require the installation tool called OBD II. Please note that not all cars have the same relearning process for TPMS codes. Some cars are going to make that recognition by themselves by driving a few kilometers, whereas some other companies, such as Toyota, Lexus or Honda for say, will require the installation tool OBD II. It is important, when buying universal TPMS, to go at a garage that is working with the proper tools to make the connection possible.
Most dealers are not equipped to deal with aftermarket TPMS, so this is why a lot of people are told that their tires do not have TPMS, or they are defective, they just cannot make the computer recognize the codes if they do not have the OBD II.