The disclosed embodiments include a valve stem assembly for a tire pressure monitoring system sensor. The assembly can comprise a valve stem body, and a grommet for purposes of engaging a vehicle wheel. The valve stem body can comprise an attachment end to be attached to a pressure sensor to determine tire air pressure. The valve stem assembly can further comprise a cap that is releasably engaged to the valve stem body which can limit movement of the valve stem assembly relative to the vehicle wheel, the cap having a closed end to cover an air transfer end of the valve stem, and a second open end to overlay the valve stem body and grommet.