All codes
Service call
SC143
SBU auto-adjust error
BScanner / optics
Level B — stop, power-cycle may clear
First check
Same cleaning as SC142, then SBU replacement.
What it means
Automatic black/white SBU adjustment failed.
Likely causes
- SBU out of spec
- Lamp
- Dirty optics
On-site steps
Parts to have on the truck
- SBU
Related codes
Confirm the subcode and part number in the FSM for this serial. Raicoh is a field companion, not a replacement for the book.