Yes you are correct, except do not remove the connector from the main board. Insert your meter probes into the end that the wires come out of. You are testing for voltage to the board, and the return voltage so it needs to be plugged in.
The LE error is pretty specific to a motor lock condition as monitored by the sensor board, and given the only parts associated with that failure would be the motor itself, the sensor board, the main board, and the harness, I would stick with those items.
One last check to make on the board would be to measure resistance between blue and white, then between red and white at the control board connector while it is unplugged and the machine is off. You should measure 10K Ohm's. If you don't the sensor board is bad.