The F70 and F71 fault codes indicate a failing CCU (Central Control Unit) resulting in lack of communication between the CCU and the Interface. If you see these codes on the screen, check the Interface’s wire harness for continuity. Then check the wiring between the CCU and the Interface. Not unlikely, there are loose or damaged (rust) connections. If the error is there, but the machine is working properly and the drum is spinning, the Interface may need to be replaced. If the drum is not spinning, the CCU needs to be replaced.