hoover dynamic Washing Machine 7+ random error 3 then 6

I have a fault with am 18 month old Hoover Dynamic 7+ Serial number 31005623. On say cotton wash the machine fills and heats OK. The cycle does not finish. I have a random error code 3. The drum is empty, the filter is clean and no water in the system. The pump works OK. If I then select the machine to off and then select drain or any other program I have error code 6. If I leave the machine for some time disconnected from the mains I can select a program and it will run until another random error 3 followed by an error 6. Do I need a new PCB or can there be another fault such as a breakdown of the insulation on the heater? I have reset the connectors on the PCB with nil effect.