Speedometer Erratic — Possible Fault Codes
Found 1 fault code associated with speedometer erratic. Codes are sorted by severity — check STOP ENGINE codes first.
SPN 191 FMI 16
Transmission Output Shaft Speed
Cummins ISX15 • Component: Transmission Output Speed Sensor (TOSS) • J1939
⚠️ Diagnostic Note:
Symptoms can have multiple root causes. Always verify with a diagnostic scan tool before replacing parts. The fault codes listed above are possible matches for speedometer erratic based on SAE J1939/J1587 fault code definitions and OEM service documentation.