There's no service mode for the motor/inverter. Check the LED on the top right side of the inverter board on top of the motor. In normal standby mode, it will flash on/off every second. With the washer running, it will flash on/off every half second. If there is an error code, it will flash at a 1/4 second rate with the number of flashes in a 6 second period depending on the error. If for example there is a mode shifter fault, it will flash 4 times quickly and then remain off until the end of the 6 second period. There is a service mode for the control board at the top of the washer behind the control panel. There should be a tech sheet tucked behind the control panel with instructions on using service mode. It will show any other error codes and allow you to go through the various functions of the washer directly.