Methods and extracorporeal blood treatment systems reposition a diaphragm of a pressure measurement apparatus (e.g., a pressure pod apparatus of an extracorporeal blood set) by, for example, controlling an air pump apparatus to move the diaphragm toward a target measuring position based on a calculated target air volume (e.g., wherein the calculated target air volume is representative of the air volume necessary to move the diaphragm to the target measuring position based at least on a monitored air pressure). For example, after the diaphragm is bottomed out or topped out, as air is added to or removed from the transducer side cavity of a pressure pod apparatus, the target air volume may be iteratively calculated until it is determined that the diaphragm is repositioned in the target measuring position.
