Problem with the water level control. With the machine completely drained of water, check air hose for kinks, trapping, holes or water in the tube. Remove hose at control panel end and blow through to check for restrictions, replace and test.
Thanks for that, it matches the symptoms, but I had already done all the checks on level, including stripping & re-soldering the area around the pressure sensor! Looks like the main board – dammit.