A tire pressure control system for a vehicle , comprising: a supply of compressed air connected to supply compressed air to a vehicle tire through an air conduit having a valve ; an air pressure sensor that senses the air pressure in the vehicle tire ; a microcontroller that is connected to control the valve to supply compressed air to the vehicle tire to increase the air pressure in the vehicle tire , and to vent compressed air from the vehicle tire to atmosphere to decrease the air pressure in the vehicle tire ; characterized in that : the microcontroller comprises instructions to: upon receiving a signal indicative of a required change in tire pressure from a current pressure to a target pressure, calculate a valve operation required to achieve the target pressure from the current pressure based on an algorithm stored in the microcontroller , wherein calculating the valve operation comprises calculating a length of time the valve is open to achieve the target pressure; operate the valve according to the calculated valve operation; measure an adjusted air pressure using the air pressure sensor after the calculated valve operation is completed; compare the adjusted air pressure to the target pressure and calculating a further valve operation to achieve the target pressure from the adjusted air pressure if necessary; and compare the results of the valve operation to the calculated valve operation and recalibrate the algorithm based on any differences. a supply of compressed air connected to supply compressed air to a vehicle tire through an air conduit having a valve ; an air pressure sensor that senses the air pressure in the vehicle tire ; a microcontroller that is connected to control the valve to supply compressed air to the vehicle tire to increase the air pressure in the vehicle tire , and to vent compressed air from the vehicle tire to atmosphere to decrease the air pressure in the vehicle tire ; characterized in that : the microcontroller comprises instructions to: upon receiving a signal indicative of a required change in tire pressure from a current pressure to a target pressure, calculate a valve operation required to achieve the target pressure from the current pressure based on an algorithm stored in the microcontroller , wherein calculating the valve operation comprises calculating a length of time the valve is open to achieve the target pressure; operate the valve according to the calculated valve operation; measure an adjusted air pressure using the air pressure sensor after the calculated valve operation is completed; compare the adjusted air pressure to the target pressure and calculating a further valve operation to achieve the target pressure from the adjusted air pressure if necessary; and compare the results of the valve operation to the calculated valve operation and recalibrate the algorithm based on any differences. upon receiving a signal indicative of a required change in tire pressure from a current pressure to a target pressure, calculate a valve operation required to achieve the target pressure from the current pressure based on an algorithm stored in the microcontroller , wherein calculating the valve operation comprises calculating a length of time the valve is open to achieve the target pressure; operate the valve according to the calculated valve operation; measure an adjusted air pressure using the air pressure sensor after the calculated valve operation is completed; compare the adjusted air pressure to the target pressure and calculating a further valve operation to achieve the target pressure from the adjusted air pressure if necessary; and compare the results of the valve operation to the calculated valve operation and recalibrate the algorithm based on any differences. <EOS>