This error code is referencing your scanning lamp just beneath the document feeder. Specifically, it is stating that the home position sensor that detects when the scanner assembly is to the further most left side is malfunctioning. However, as a copier technician, I would advise against pursuing any sort of remedy yourself, as there are numerous high voltage components on the scanner assembly that present a possible danger. Not to mention replacement parts are extremely expensive if you accidentally blow anything out.
My advise, contact someone who is trained in servicing these machines.