Bosch Dishwasher SHV4303UC - Does not drain.

Question

Help please. This 7 yr old dishwasher is not draining at the end / beginning of the cycle. I checked both filters which were clear. Disconnected the drain line to the sink and it was clear. Pressed the 2 buttons together for 3 seconds per manual to reset. Turned off circuit breaker to reset. Nothing helped. This happened 2 yrs ago and I believe the circuit board was needed and was replaced. When you start the machine you hear a slight hum for 20 seconds before the wash cycle. Any suggestions would be greatly appreciated.