If you have verified the by-pass solenoid is not operating correctly, follow the steps below. If you have not tested the solenoid refer to- Operating the bypass solenoid.
Check the wiring to make sure the wires are connected in the proper location on the drive board. (Specifically verify the wires from the solenoid are plugged into the correct location)
If the solenoid is stuck clean the solenoid and retest.
Refer to the video below for the cleaning procedure.
If the bypass solenoid is still not operating properly, replace it.