Unofficial repair guides indicate this error is a problem with the heating element, wiring, thermostat or the control board, in particular "the relay". This matched the symptoms as the machine ran cold but the communication error was still a mystery, so I decided to investigate the heating system. I removed the top and side panels simply by unclipping them.
The main electronic control unit is easily accessible at the bottom back right corner of the machine after removing its clip on cover.
The heater connections are the thick red wires and can be probed by removing the connector and inserting 6.4mm spades into the female connector slots. The other connectors are edge connectors directly onto pads on the PCB. They can be probed by putting them over a piece of veroboard as they have the same 0.1" pitch as the tracks.
Research with Google informed me that there are two generations of heating system in Bosch dishwashers. The original heater was like a kettle element that the water flows around.
It just presses into the inlet tube of the zeolite tank and is sealed by the top o-ring. The peg on the side ensures the correct orientation.
this video that showed how to remove the base of the same generation machine. It wasn't one with a zeolite heater but the basic construction was the same.