TPMS Knowledge Base

What is a Tire Pressure Monitoring System?

A tire pressure monitoring system or TPMS is an electronic system for monitoring the air pressure in a vehicle tire and automatically transmitting a warning to the driver in the event of an under or over inflated tire. These systems have been legislated to be progressively installed on all new passenger carrying US vehicles and a similar move is taking place worldwide.

The majority of systems use Direct tire sensors which transmit real time tire pressure information to the driver of the vehicle either via either a dashboard display or a warning light. The sensors are physical pressure transducers which are attached to the back of the valve stem or are in a form which is banded to the wheel. The sensors are manufactured by International companies such as Schrader, Siemens, TRW, Pacific, Lear and others. There is no common technical standard for the sensors and the OE's and suppliers have generated a multitude of sensor designs.

The sensors also transmit data such as their unique sensor ID, temperature and pressure, battery life and other diagnostic information. This data is sent to the Engine Control Unit (ECU) or specific receiver on the vehicle. Those vehicles which have graphical displays of the TPMS positions can then show on which wheel there is a problem.

Why is there a need for Tire Pressure Monitoring?

Tire Pressure Monitoring helps drivers to properly maintain their vehicle tires, improves vehicle safety and aid fuel efficiency. The National Highway Traffic Safety Administration (NHTSA) in the US has estimated that 533 fatalities per annum are caused by tire defects in road accidents. Adding TPMS to all vehicles could avoid 120 of the 533 yearly victims and save as many as 8,400 injuries every year. Sécurité Routière (the French Institution for Road Safety) estimates that 9% of all fatal road accidents are attributable to tire under-inflation and the German DEKRA estimated that 41% of accidents with physical injuries are linked to tire problems. Tires leak air naturally and over a year a typical new tire can lose between 3 and 9 psi. As most drivers only check their tires at service intervals and when problems occur there is significant scope for fuel savings and efficiencies.

Given this background the US Federal government has legislated for the mandatory use of TPMS. The TPMS mandated by the US law must warn the driver when a tire is under-inflated by as much as 25%.

What is a Tire Pressure Monitoring Tool?

There is no common standard for the TPMS sensors with variations including frequencies, modulations, data structure, communications protocols, mechanical fitment and many other factors.

When TPMS is installed and tested in the car plant by Bartec the process includes:

  • The TPMS sensors are attached to the wheel during the Wheel and Tire assembly process
  • The wheels are attached to the vehicle. This is the first time at which the TPMS can be clearly associated with the vehicle
  • Fixed radio antennas are used to extract the unique IDs (and other data) of the TPMS, associate them with their wheel position on the car and the Engine Control Unit (ECU) can then be programmed with this data
  • The car is then run through Rolls Test where the system is tested

Similarly the car dealer or tire shop needs to have a portable TPMS tool available to test the TPMS and read the wheel sensor ID and program the car's ECU in the event of TPMS battery failure, broken sensor/valve, or other repair or replacement of wheels and sensors for custom wheels, winter tires, tire rotation etc. The tool needs to be able to turn out the TPMS warning light.

Please browse our website for more information about Bartec USA LLC and our range of TPMS Tools and our professional Tire Pressure Monitoring System support, then call toll free 855-877-9732 and speak to one of our team or e-mail us at sales@bartecusa.com.


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Frequently Asked TPMS Knowledge Base Questions

All tires will lose air naturally over time, so it’s recommended that you check the pressure in all your tires, including the spare, at least once per month. Road conditions, weather conditions or other circumstances may warrant checking the pressure more often. Remember to always use a quality tire gauge when checking tire pressure.
A TPMS [or Tire Pressure Monitoring System] is comprised of four basic components. A sensor, located in the wheel, a receiver module located somewhere on the chassis or body, a warning light/MIL, and a placard label. The sensor is designed to measure pressure and then transmit that data via a radio frequency [RF] signal to the receiver at which point the data is converted into a digital output. The digital information is processed and if a low-pressure condition [more than 25% deflated] is detected, a low-pressure warning is indicated on the instrument panel.
You should stop asap to inspect and make sure you don’t have a tire rapidly losing pressure. Riding on an extremely low tire can cause an accident and or ruin a tire. If the tires look to be holding pressure, find a service center that can check your air pressure when it is possible.
As of model year 2008, the United States Department of Transportation (through NHTSA) requires an installation of a Tire Pressure Monitoring System to all new passenger cars, multipurpose passenger vehicles, trucks, and buses that have a gross vehicle weight rating of 10,000 lbs. or less (except those vehicles with dual wheels on an axle). The legislation requiring TPMS was passed in reaction to Congressional hearings on vehicle rollover deaths caused, in part, by vehicles with under inflated tires.
Many factors affect tire pressure including ambient temperature changes and tire damage such as punctures. Tire pressure drops approximately 1 psi for every 10°F drop in ambient temperature. Additionally, tires can lose as much as 1.5 psi per month as air escapes the tire and rim naturally.
No. Under 49 U.S.C. 30122(b), “A manufacturer, distributor, dealer or motor vehicle repair business may not knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard.”
A flashing TPMS light, or MIL [malfunction indicator light] means that one or more components of the TPMS is NOT functioning properly. Most often the TPMS Sensor battery has expired and therefore no longer communicates to the vehicle. After a period, a “dead sensor” will be “missed” by the receiver and send the necessary warning signal to the instrument panel. The length of time for this to happens varies by vehicle manufacturer and type.
Low tire pressure is one of the leading causes for the following: Blowouts causing an accident involving death/injury, Excessive Tire Wear, Poor Handling, Diminished Fuel Economy, Reduces the effectiveness of the Vehicle Stability Control System.
Typically this indicates a tire/s that have a low pressure condition of at least 25% below the pressure listed on the placard on the driver’s door.