Have taken this one back to the workshop, been out to this one twice and both times it worked fine while I was there.
Customer tells me that it starts up fills with water and will continue to wash all day none stop, and when the door is openned the water is cold.
A very common problem with Bosch dishwashers is low water levels which will cause a no heat fault. Check all the usual inlet hoses/pressure chambers etc for blockages that might cause low water levels.
When fully running the water should just about cover the base of the tub and reach about 1/3 to 1/2 up the salt lid cap. Any less than this and it’ll give you probs.