Hi, welcome. So many things to check that might throw this up, proper diagnostics required, and being intermittent is a PITA so you might have to throw in wiggle, hot, cold, water/damp tests. Certainly start at the battery and main power and earth connections and leads, then you might test fuses, relays, ignition/start buttons, modules, wires, connections, etc.. Then the computer systems are complex and intertwined so if there is a second or more contributing problems it could be back loading from lots of sources. The CAN bus can be off from the starting point and/or or points playing it up. You've not put which (part)year your car is or if it's DSG and or KESSY (light or to me full nuisance), IIRC the CJZD is the 1.2 TSI with extra turbo(?). Intermittent or not for electrical stuff on a car I don't know I'd (not that I know or can do much) always start at the very basics, that are often missed by even the knowledgeable and experienced, from battery posts on, are the terminal posts clean, and terminal post clamps clean (inside and out) and securely fitted, then main battery leads and their connections, check battery state of charge and condition - then plug in the scan tool to see what it has. Let us know how you get on if you're lucky you might get someone good at diagnostics and find it's something quite straightforward and easy fix despite it looking so dramatic. See this chap who gets similar with other cars/vans and how he solves them. - https://www.youtube.com/@mrautoservices7354