Once you've inflated all tires to the correct pressure, drive the vehicle for a short distance (a few miles) at speeds above 20 mph. The TPMS sensors will re-read the pressure and the light should turn off automatically. If it doesn't, there might be a problem with one or more of the TPMS sensors, a faulty sensor, or a problem with the system itself, and you'll need to have it checked by a mechanic.