All codes
Service call
SC601
Engine–controller communication error
BCommunications
Level B — stop, power-cycle may clear
First check
Reseat engine I/F, then firmware pair, then IOB/controller.
What it means
First-level engine I/F error. Often a cousin of SC670/672.
Likely causes
- I/F cable
- Firmware mismatch
- IOB
- Controller
On-site steps
Parts to have on the truck
- Engine I/F cable
- IOB
- Controller
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.