On our Bosch machine the 40 degree programme works fine but if you select just the spin cycle or the 30 degree programme it doesn’t work. I did wonder if it was the brushes (changed a few years ago) but doesn’t make sense if the 40 degree cycle fully completes (which must include a spin). When they failed before the drum wouldn’t turn at all.
Model number is WFL12440 and I reckon it’s about 8 yrs old
Would check the motor brushes, drain pump, door interlock, inlet solenoid valves & heater as standard on any appliance that age giving those kind of problems.