Diagnostics of the hydraulic power steering (HPS) is required in the presence of the following shortcomings in operation: shocks, vibrations and knocking sounds coming from the steering wheel, steering play, uneven effort when turning the steering wheel, mismatch between the steering wheel position and the angle of rotation of the wheels, switch of the steering wheel back to the neutral position after turning, too much effort for turning. In the course of diagnostics of the hydraulic circuit, an expert uses special hydraulic equipment to check whether the HPS pump generates sufficient pressure and to evaluate the tightness of the mechanism.