Method for operating a hydraulic actuator

A method for operating a hydraulic actuator (K0) for a prime mover or a drive device of a vehicle, the method comprising:

• determining that the hydraulic actuator (K0) is to be actuated via an actuating system controllable to adjust a fill level of a liquid operating medium in the hydraulic actuator (K0), the actuating system having a pressure-adjusting device controllable by an electronic control unit, the hydraulic actuator comprising a friction-locking shift element (K0);
• detecting an operating variable (g, s) of at least one prime mover (EM, VKM) of the vehicle, the operating variable (g, s) being a torque or a rotational speed of the at least one prime mover (EM, VKM), the operating variable (g, s) being influenced by a filling state of the hydraulic actuator (K0) and indicative of pressure conditions in the hydraulic actuator (K0), the pressure conditions in the friction-locking shift element (K0) being inferred based on a temporal profile of the operating variable (g, s), the operating variable (g, s) being separate from an actuator operating variable (p) of the hydraulic actuator (K0) and an actuator operating variable (p) of the actuating system;
• pressurizing the hydraulic actuator (K0) during a fast fill phase to one or more pressures over a fast fill time period in response to determining that the hydraulic actuator (K0) is to be actuated, with the fast fill time period and the one or more pressures being adjusted as a function of the operating variable (g, s) under certain operating conditions;
• and
• pressurizing the hydraulic actuator (K0) during a pressure build-up phase after the fast fill phase.