What is SPN 5245 FMI 31:
This is a general warning code, where FMI 31 means abnormal but not defined — usually a catch-all for early warning signs of deeper system issues.
Often triggered by unresolved minor faults or pending emission system problems.
Why This Happens
- DEF, NOx, or regen faults pending but not active.
- Outdated ECM software.
- Low-quality fuel or DEF.
- Faults suppressed by another system.
How to Fix It
- Scan for inactive or pending codes.
- Resolve any sensor signal delays or mismatches.
- Update ECM firmware.
- Run a full regen and emissions system test.
- Clear code and watch for reappearance.
How to Avoid It Before It Happens
- Fix even minor DEF or emissions faults quickly.
- Keep ECMs and modules fully updated.
- Use only high-quality consumables.
- Leverage Clue’s Reports & Analytics to track sensor signals and monitor emissions system performance to catch early signs of trouble before they escalate.