Whirlpool Duet Sport F01 - won't do final spin

Hi. I have a 4.5 year old Whirlpool Duet Sport Washer that will not perform the final spin cycle (after draining), and it gives an F01 error. This was after we were getting an F24 error for a drain problem (we cleared that with no problems). A week after solving that, we started getting this error intermittently (once in 20 washes or so), I’d run the "Drain and Spin" cycle and it would be ok. Now, nothing. We’ve looked at the connections on the CCU and they seem ok. The drum does spin properly during the wash and rinse cycles, but NOTHING happens when it’s time to spin. Any ideas?? Thanks in advance for your help!