Answer Hello Maggie. Communication between the Central Control Unit and the MCU has not been detected. Possible Causes • Check door switch operation. Faulty switch may interfere with power to MCU. • Check drive system for worn or faulty components. • Verify continuity in cable between CCU (MI3 & MS2) and MCU Read More... Answered by AppliancePartsPros.com | Wednesday, July 22, 2015