Unfortunately it was not solved and problems mentioned above probably wasn't the cause. It seems that something wrong is with the hotend heater, just before the VSSA error it started to cooling down and then started to heat while made VSSA error (didn't see that behaviour before there was only VSSA errors).
Maybe the new hotend heater that I've mounted is damadged and has internal shortage or arcs randomly.
This is how it looks.
vssa1.jpgvssa2.jpg