F3E3 is thermistor fault. You have mentioned that it no longer fills with warm or hot water, only cold? Bad thermistor surely could cause that.
The thermistor is in the water valve assembly, not in the board. Run Test #5 on the Tech Sheet. If wrong temperatures are reported then check the thermistor directly with a meter for proper resistance/ohms on several temperature points. Change the valve assembly if the thermistor shows wrong resistance/ohms on the meter tests.
If the thermistor tests correct ohms, then the board may be bad on reading the signal from the thermistor, so replace the board in that case.