dishwasher flashing lights,not heating water?

indesit 125 s..had for a while no probs,,,2days ago,thing switches it's self on and pump runs ..2 lights on front flash 2cnd in row of 3 and start /pause light.will run on rapide,arms rotate,fills uses tablet,but will not heat up water,,, if you swithch it off within five mins lights flash and pump starts,,,to stop have to swithch off at plug..