What Causes Cummins SPN 157 FMI 18? Cummins SPN 157 FMI 18 is an indication of a fault in the engine’s fuel system. This fault code is triggered when the engine control module (ECM) detects an issue with the fuel pressure sensor circuit. The ECM monitors the fuel pressure sensor signal and compares it to a predetermined value. If there is a discrepancy between these two values, then this code will be set. Common causes of Cummins SPN 157 FMI …
