A tire pressure sensor is designed to warn that one or more of your tires is underinflated. All cars built since 2007 are required to have this system. The most common sensor uses a battery and operates via a wireless transmitter mounted inside the rim of your tire’s wheel. When it detects low pressure, it sends a signal to your vehicle’s computer system that shows up on your instrument panel as an icon of a tire or some other alert. Most warn of low pressure without indicating a specific tire, while more advanced systems can flag an individual wheel or indicate the pressure in each tire. The batteries in tire pressure sensors last around five to seven years but sometimes they can fail earlier. The sensors can also be damaged from potholes or other sudden jarring. Replacing the sensor is easy for a tire retailer or your dealership service department. Your service technician will also electronically reset the system after replacing the sensors or whenever you replace your tires.