Indirect TPMS, or Indirect Tire Pressure Monitoring System, is a technology used in vehicles to monitor tire pressure without using dedicated sensors in each tire. Instead, it relies on the vehicle's existing wheel speed sensors, which are part of the anti-lock braking system (ABS). By comparing the rotational speed of each tire, the system can detect differences that indicate a loss of pressure in one or more tires. When a tire loses pressure, it typically becomes smaller in diameter, causing it to rotate faster than properly inflated tires. The vehicle's onboard computer analyzes this data and alerts the driver through a warning light on the dashboard if it detects a significant pressure drop. This system helps maintain safety and fuel efficiency by encouraging timely tire maintenance.