Forestry CAN Bus Diagnostics: A Field Engineer’s Step-by-Step Guide to SPN 639 FMI 9 Troubleshooting
It was 14°F and the snow was coming down in thick, wet clumps somewhere in a spruce block north of Thunder Bay. I was standing on the track of a 2018 Ponsse Ergo harvester that had decided to park itself mid-cycle. The head wouldn’t feed. The dash showed one active fault: SPN 639 FMI 9. The operator, a […]