All codesService call
SC621
ADF connection error
BCommunications
Level B — stop, power-cycle may clear
First check
Connector in the hinge and the ADF presence sensor.
What it means
ADF present/connection bit failed. Similar to 610, often after an ADF swap.
Likely causes
- Hinge connector
- Wrong ADF for the model
- ADF board
On-site steps
Parts to have on the truck
Confirm the subcode and part number in the FSM for this serial. Raicoh is a field companion, not a replacement for the book.