Pioneer SUPER TUNER KEH-M5550 Owner's Manual page 14

Error Mode
Note:
14
Treatment
Wipe the dirt off the disc.
Exchange the disc if it is scratched.
Confirm that the disc has been inserted
right side up.
Wipe the dirt off the disc.
Exchange the disc if it is scratched.
Cause
multi-play CD player.
Electrical or mechanical system fault.