LG WD12124RD Te fault

LG WD12124RD —–te fault
Went to machine switched on—-te fault.
Replaced wash thermistor,still te fault.After checking heater ok I then tried to reset machine by first switching off then back on.This didnt work so i tried to enter diagnostics but couldnt.After checking wiring and connections I then replaced board.
When i switched back on te quickly flashed up then went off.At this point I was able to switch back on and run program ok.I then ran it through diagnostics it seemed to work ok,although a couple of times te momentaraly flashed up.
I left machine on test only to find that appliance had later stopped on te.
I ordered a new display board up thinking that could now be the only cause but the same fault is happening.
Is it possible that the old fault has to be cancelled from the memory before you can use again(but a new control board should have seen to that)
ANY ADVICE WOULD BE GREATLY APPRECIATED—–STEVE