Shift motor drive malfunction 
<When JS-504 is installed> • The shift home sensor (PS6) is not blocked after the set period of time has elapsed after the shift motor (M2) is turned ON (start of moving to the home position.) • The shift home sensor (PS6) is not unblocked twice in a row after the set period of time has elapsed after the shift motor (M2) is turned ON (start of moving to the shift position.) <When FS-527 is installed> • When moving to the front (home) position: The tray 1 shift home sensor (PS25) is not turned ON even after the set period of time has elapsed after the tray 1 shift motor (M16) is turned ON. • When moving to the rear (shift) position: The tray 1 shift home sensor (PS25) is not turned OFF even after the set period of time has elapsed after the tray 1 shift motor (M16) is turned ON.