This is a tire pressure reset instrument, or a learning proposal. After each tire rotation, tire, body control module and tire pressure sensor replacement, the sensor re matching procedure must be performed to ensure the correctness of tire pressure value acquisition and display. Operation steps: 1. Make sure the car is in TPMS learning state or mode. 2. Follow the vehicle maintenance procedure, hold the instrument in turn (front left, front right, rear right, rear left), align it with the sidewall of the tire near the valve stem (the inlet for gas filling) and press the reset button. 3. At this time, the green LED light (TX light) will be on, indicating that the signal is being sent. When the car buzzer is heard, the matching is successful. 4. Match other tires in turn. Specifications: The compact design makes it portable and easy to carry. Check the tire pressure in real time. Only certain designated diagnostic tools can be used to read out the tire pressure sensors on 2012 and later models. It has diagnostic sensing function. It is universal and suitable for most cars. For GM vehicles equipped with a 315 or 433 MHz Tire Pressure Monitoring (TPM) system, the "Sensor relearn procedure" must be performed after the tires are rotated, the remote keyless entry receiver module is replaced, or the tire pressure sensor is replaced. This relearning procedure can be performed using special tool EL-50448. This procedure also applies to 2014 GM models. Package Included: 1 x Tire pressure reset instrument