The F70 fault code signals failing communication between the interface control board and the main control board. This can occur due to a glitch or power surge. Reset your washer by unplugging it for about one minute and then plugging it back in. In most cases, resetting clears the error.
If the code is still there, remove the top and check the wire harnesses and connections between the boards. Check connections on both boards. Disconnect them one at a time, check all pins for damage or corrosion, and reconnecting them.
If the error appears again, most likely, the interface is faulty or shorted. The F71 “heartbeat failure” error code means that the interface control board needs to be repaired or replaced.