A “6” error code is a cheating attempt, if it ends with a “4” the side scan sensors are out of adjustment or calibration. When was the last time you calibrated the validator? I’d try cleaning and re-calibrating the validator before I get to anything else. What version is the validator, it'll be on the side of the validator? It should be a v3.60. When was the last time it was serviced, it will also be on the side of the validator. The optimum thing to do would be to convert it over to a Mars validator. I'll PM you the XE validator manual and the calibration procedure.