Over time, TPMS sensors can start going bad. It's important to keep them working correctly as long as your car is on the road. You can't risk the chance of having a blow-out at highway speeds due to lack of air. Under-inflated tires can also cause excessive tire wear and lower gas mileage. Both will result in higher maintenance costs. If you discover your sensors are giving false readings - or no reading at all - then you need to replace them immediately. Keep you and your car safe by purchasing brand new replacement sensors.