When i start the big compartment regardless off the setpoint i can hear first that the hgv1 valve opens and just as the compressor turns it shuts off immediately. The display goes black. After 5 seconds the display starts up again and it first say "initz" then directly it shows actual temperature and setpoint and tries to start again with the same fail.

No fault code is registered, A00

It doesn't matter if I run with standby or road compressor, same problem occurs.

BUT, if I run it on defrost it doesn't shut down, so just checked micro logic and on defrost for the first 5 min the 2 evaporator fans are not engaged. So I disconnected them and started it on setpoint (0) but same problem.

A college changed the relay card but same issue, he also measured installation for short circuit to evaporator fans but nothing.
Connected manometers and pressure is OK.
College changed both micro processors master and slave, still the same problem.

This system is operating on 12V, checked wiring for ground ok. Tested with external powersupply same problem.

The small compartment, freezer works normal.
Any suggestions?