If you see that your tyre is low or flat but the TPMS indicator light does not come on, chances are that you have a faulty sensor. Conversely, if the light comes on but all tyres have stable and correct pressure, this also may mean that you have a faulty sensor, especially if the light blinks when you first start the vehicle. Take your vehicle to a tyre service professional to have them check the sensors, however remember to insure your tyre pressures are checked and correct before driving.