Central tire pressure monitoring system

A central tire pressure monitoring system interfaces with a tire inflation system to check the pressure in all of the tires of a trailer of a heavy-duty vehicle at a single interface location on the trailer, without the need to provide power to the trailer. The tire inflation system includes a source of pressurized air, at least one tire, a pneumatic conduit extending between and fluidly connecting the source of pressurized air to the tire, and a controller fluidly connected to the conduit. The monitoring system includes a monitoring valve fluidly connected to the conduit between the controller and the tire. The monitoring valve includes a port, and a test tool selectively fluidly connects to the monitoring valve port to enable air flow from the tire to the test tool. An indicator fluidly connects to the test tool and provides a reading of a pneumatic pressure in the tire.