In SAE J1939, the acronym SPN stands for Suspect Parameter Number and represents the identity of a J1939 parameter. Every J1939 parameter has a unique SPN, which is 19-bits wide, assigned to it by the SAE committee when the parameter is defined.
The main purpose of the suspect parameter number is to identify a parameter when a failure has occurred. Every failure is identified by its SPN and FMI fields.
