Make sure the drain pump is getting power when it's supposed to be operating. If so, it needs to be replaced. If not, could be a control board issue. With this design, the control board commands everything. No direct feedback from the tub drive motor, it's a smart slave. The motor/inverter has blinking light codes and pretty much the only solution is to swap out major assemblies. Strange blinking light equals need a new drive motor inverter. If no strange blinking light, needs a new control board and or sensors.