TPMS Relearn Tool Usage: 1. Need 1x Pcs 9V battery to work(not included) 2. Set the car in TPMS learning mode. (car horns twice) 3. Starting from the left front tire, the antenna of the dedicated tool for tire pressure monitoring is facing upwards against the tire sidewall near the rim of the valve stem to start the antenna. Press and release the button and wait for the speaker to emit a chirp.Once the speaker is chirping, the sensor information is read and the turn signal to be read at the next position will light. 4. Follow this order to rest TPMS one by one: Front left, front right, rear right, rear left. 5. After all sensors reset, the car horns twice, the TPMS re-learn finished. How to switch between: Hold the power button for 3 seconds and 2 LEDs flashing 2 times, selected brand's LED flashing 2 times. If the Green LED flashing, means TPMS relearn tool in GM mode, if the Red LED flashing, means TPMS relearn tool in for Ford mode. Suitable: For GM series (for Opel / for Chevy / for Buick / for GMC/ for Cadillac) and for Ford series (for Lincoln / for Mercury). Material: ABS colour: black+orange Package Contents: 1 x TPMS Relearn Tool