Before replacing the line sensor, Kers, I think it would be wise to check all your inks and printheads. Sometimes error 55:11 is caused by a faulty printhead. It won't hurt to replace the line sensor, but it could be other things as well or instead.
In any case, it shouldn't hurt the printer to continue printing. If your printheads and inks are fine and the diagnostic test looks good, then just keep on printing....
Mark