Firstly check you travel control unit which the pedals attach too.
Secondly I would be checking the servo unit on top of the pump. Also check the pressures on the y and z hoses on the pedal assembly. When you start the machine both pressuresides should come up together. When you slowly press a direction pedal , one will increase.at a difference of 4 bar the wheels should start to rotate.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.