sound like a bad timer the part # for the timer is AP2804302

Classic anti-flood symptom.
There is a float switch in the bottom of the plinth that when activated puts the machine into continuous drain mode.
If this occurs every other day or so then the water is drying out during this time and puts the machine back into run mode.
The next time it fails to run, tilt the machine back to drain any water out of the bottom and see if that fixes it.
Causes of flooding are due to operator chucking the soap tablet in the sump of the dishwasher on start up. The foam action creates a false rise in water level that then fills up the drip tray in the plinth.

Of course this is one of the most common of courses and I could go on to explain others but that is for another day. I'm sure this will fix it for you.

Kind regards Tony

usually if you advance the timer one click or two at whatever point it seems to be getting stuck at and it will continue until another point where it again gets stuck, it usually means that it is some sort of heating circuit problem. most often the timer is not the problem but more like a thermostat. i believe on that model, there are 2 thermostats in the door area, near the detergent dispenser ... most of the time, one of them is not sensing heat properly.. "thermomastic' is important when replacing those thermostats as heat transfer is very important..