Tire Pressure Monitor System The tire pressure monitor system is designed to alert the driver when one or more the four regular tires is significantly under-inflated. If the pressure in any monitored tire drops too low a warning icon appears in the combination meter. If the pressure drops further the icon begins to flash to urge immediate attention. Reinflate the low tire to the proper pressure and the light will go off after a few minutes. The light will stay on when using the compact spare tire and will go off a few minutes after the original tire is properly inflated and reinstalled. the system needs to be reinitialized whenever new wheels or tires are installed. See your owner’s manual or your Toyota dealer for details.