Vehicles SPN 1569 DTC Troubleshooting Posted by David T on August 2, 2022 Read Next → Vehicles SPN 4364 FMI 18 DTC Explained, Troubleshooting Vehicles SPN 4334 FMI [2-18] Troubleshooting Explained Vehicles SPN 3264 FMI [0-16] Troubleshooting Explained SPN 1569 FMI 31 is a diagnostic trouble code for engine protection torque derate. Troubleshoot: DEF sensors, update ECM David T Read Next → Vehicles SPN 4364 FMI 18 DTC Explained, Troubleshooting Vehicles SPN 4334 FMI [2-18] Troubleshooting Explained Vehicles SPN 3264 FMI [0-16] Troubleshooting Explained