It is well known that often hydraulic pumps are resource-limiting components of the units in whose design they are included, and the condition of the hydraulic pump determines the performance and efficiency of the entire unit. The purpose of the work was to develop a prototype of a diagnostic tool that provides monitoring of the technical condition of hydraulic pumps during operation. An analysis of the tools produced by the Federal Scientific Agro-Engineering Center VIM for diagnosing the technical condition of hydraulic pumps of agricultural machinery was carried out. The material of research was a prototype of a tool for diagnosing the technical condition of hydraulic units, which was based on the method of amplitude-phase characteristics for rapid assessment of the technical condition of pumps during operation. On the base of our research we came to conclusions that for further development of the technology and subsequent implementation of the presented prototype in the process of diagnosing hydraulic pumps by pulsation coefficient it is necessary to increase the controllability of hydraulic systems of agricultural machinery by installing diagnostic points for connecting pressure sensors. Also together with manufacturers of hydraulic units, develop criteria for nominal, permissible, limit states, characterized by both the supply coefficient KQ and the pulsation coefficient ɛ.