StelNo

Hi everyone, I´ve read here few topics related to this fault codes and I˙m still puzzled with it. I drive Octavia 2017, 1.6 TDI, 225k km. On random I am getting fault, coil sign start to blink sometimes also check engine starts lights up and car goes into limp mode. On diagnostics it`s always P256400 Turbo charger boost control position; sensor circuit: low and P256300 Turbo charger boost control position; sensor circuit: range/performance. Tested vacuum, tried to change selenoid valve, change connector of actuator because it was a bit damaged. Fault persists, and on random occasion. Sometimes it`s on already on car startup sometimes during drive and sometimes it droves perfectly. Car was few days with my mechanic and he could not replicate fault, car was going perfect for few days and all parameters was good. He than made regeneration of DPF. Of course that did not change anything after a day fault was there again. Coil blinks, sometimes check engine, always limp mode. Has anyone idea what could i do? I`m thinking of replacing all vacuum tubes just to be sure and maybe cleaning of turbo. BTw A year and a half ago the fault was on and I replaced actuator, the fault persisted and after mechanic cleaned some connectors fault was gone, and drove for year and a half wit no errors.