What is SPN 4364 FMI 18 Code? How to Fix It?
SPN 4364 FMI 18 indicates a valid signal that is lower than expected, often linked to NOx sensors and aftertreatment systems in off-road machinery. This guide explains common causes such as wiring issues, sensor aging, and exhaust leaks, along with a practical troubleshooting process. Follow a clear step-by-step approach to identify the root cause, avoid unnecessary part replacements, and restore engine performance efficiently.












