Frequently Asked Questions
A Tire Pressure Monitoring System (TPMS) sensor is a device that is installed in a vehicle's tires to monitor tire air pressure and temperature. The TPMS is an electronic system that connects the sensor to a monitor on the vehicle's dashboard to indicate whether or not the tires are properly inflated and to alert you when a tire is significantly underinflated. The primary function of the TPMS sensor is to alert the driver when tires are underinflated or overinflated. When a tire loses pressure, TPMS alerts the driver with a flat tire warning light. A tire sensor is typically mounted on the inside of each wheel of your vehicle.
Direct TPMS
Direct TPMS measures the air pressure in each tire using a sensor mounted in the wheel. When the pressure in a tire drops below 25% of the recommended inflation level, the sensor notifies the vehicle's computer system and the low tire pressure warning light on the dashboard illuminates. Each sensor has a unique serial number. This allows the system to distinguish not only between itself and systems on other vehicles, but also between the pressure readings for each individual tire. Direct sensors are a pressure gauge in the valve stem that communicates with the vehicle via radio waves.
Indirect TPMS
Indirect TPMS works with your vehicle's anti-lock braking system (ABS) wheel speed sensors, eliminating the need to mount additional components on the wheels. These sensors measure the rotational speed of each wheel. Based on the rate of rotation of each wheel, the computer can interpret the relative size of the tires on your vehicle. If a tire is underinflated, it's diameter will be slightly smaller, so it will rotate faster to cover the same distance. Your car's computer system detects this information and triggers the dashboard light. So an indirect TPMS doesn't actually measure tire pressure. Instead, it simply measures how fast your tires are spinning.
Most TPMS sensors are powered by batteries built into the sensor, and these batteries are not replaceable. The lithium-ion batteries in TPMS sensors can last from five to 10 years, with an average life of seven years. For older TPMS sensors, five to six years is more typical. TPMS lifetime is related to the number of RF pulses the sensing devices transmit. TPMS sensors do not transmit a continuous signal, but only when the vehicle is in motion. As a result, sensor battery life depends on the amount of driving you do over time and the conditions you drive in.
Step 1: Removing stem cap of your tires.
Step 2: Demount the tyre.
Step 3: Remove the existing sensor and clear the valve stem hole of any dirt or corrosion.
Step 4: Remove the washer, nut and cap from the new valve stem.
Step 5: Install a new sensor through the rim hole.
Step 6: Insert stem, place the washer.
Step 7: While holding the sensor in position, tighten the sensor nut.
Step 8: Locate the sensor body on the other end of the valve stem.
Step 9: Hand tighten to secure, then tighten connecting screw.
Tire Pressure Monitoring System (TPMS) sensors are not universal. Car manufacturers invest in different TPMS technologies, so you need to check the compatibility of the tire pressure sensors with your vehicle. They come in different types and are designed to work with specific vehicles. In addition, the sensors are specific to the vehicle make and model, and sometimes even to the wheel of the vehicle.
