Hi, my name is XXXXX XXXXX I have been in the home improvement and repair field for 20 years. I will be very glad to help you today.
The thermostat located on the bottom side of the unit could cause this error code. Testing the thermostat with a volt meter should be done before purchasing any parts. The most likely issue is the control board. You can very likely diagnose for sure by removing the screws around the door, Bosch uses torque head screws on most of their appliances. With the screws removed the control panel will release and fall forward, you will need to unclip the control board from the plastic housing. On the bottom of the control there are several locking tabs, depressing them with a small screwdriver will release the board from the housing. With the dishwasher control removed you can open the plastic housing and expose the heater relay. The relay will likely look burnt. Also look for the missing or black solder mark on the board. If you discover that is the case then use the numbers printed on the board to order the proper replacement board.