All codes
Service call
SC220
Laser synchronization (SOS) error
BLaser / writeCommon field call
Level B — stop, power-cycle may clear
First check
After any laser unit reseat. Confirm the unit is fully down and the sync harness is locked.
What it means
Start-of-scan / sync detect beam never arrived. LD, polygon, or SOS sensor/harness.
Likely causes
- LOSU not seated
- LD failure
- SOS sensor / harness
- Polygon not spinning
On-site steps
Parts to have on the truck
- Laser optics unit
- SOS harness
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.