Posted on November 14, 2022 by Jack CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – Troubleshooting and Repair Manual FAULT CODE 16-fc689Fault Code Path Selection Is the engine an ISM? Go to 16-fc689ism Is the engine an ISX? Go to 16-fc689isx Last Modified: 30-May-2006 Feedback / Help