Tech a says that a direct tpms system uses a pressure sensor located in each wheel. This is a TRUE statement.
Explanation:
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. A TPMS reports 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.
Direct TPMS uses a sensor mounted in the wheel to measure air pressure in each tire. When air pressure drops 25% below the manufacturer's recommended level, the sensor transmits that information to your car's computer system and triggers your dashboard indicator light.
Mounted inside a tire assembly on valve stems or wheel rims, the sensors are usually powered by 3-volt lithium ion batteries, but some use 1.25-volt nickel metal hydride batteries. There are developments underway that promise battery-less sensors in the future, having the potential to dramatically change TPMS markets
The tire pressure monitor system that uses a valve-stem-type transmitter is the direct reading type of TPMS.
