A DEF injector is configured to inject DEF into an exhaust system of a vehicle. A DEF pump includes an electric motor configured to drive a compression mechanism and pumps the DEF to the DEF injector. A pressure sensor is configured to measure a pressure of the DEF output from the DEF pump. A sampling module is configured to, based on a rotational position of an output shaft of the electric motor, selectively output samples of the pressure. A measurement module is configured to determine a measured pressure at the pressure sensor based on a present one of the samples and a last one of the samples output before the present one of the samples. A pump control module is configured to apply power from a power source to the electric motor based on a difference between the measured pressure and a target pressure.