A method of detecting a transmission fault of a wheel unit belonging to a tire pressure monitoring system which includes a plurality of wheel units associated with a central unit placed in the vehicle. The method includes: a) transmitting messages by the wheel units, b) receiving these messages by the central unit having an active antenna exhibiting a plurality of reception lobes each able to receive a message originating from a predetermined wheel unit, c) when a lobe has received a message originating from the wheel unit with which it is associated, deactivating this lobe, d) repeating steps b) and c) until all the lobes have received a message, e) if after a predetermined time span all the messages of all the wheel units have been received, all the lobes are reactivated, in the converse case the wheel units whose messages have not been received are counted “mute”.