Vehicle Fault Codes
4,200 diagnostic trouble codes — standard OBD-II and manufacturer / heavy-duty. Search or pick a family below.
Standard
OBD-II Codes
3,381Cars, vans & light vehicles — the standard SAE diagnostic families (P powertrain, B body, C chassis, U network).
P 3378 B 1 C 0 U 2 Browse OBD-II codes Manufacturer / Heavy-DutyCummins Fault Codes
819Diesel trucks & equipment — Cummins J1939 (SPN/FMI) codes grouped by after-treatment system (DPF, EGR, SCR & DEF), with tuning & delete guidance for AltTune dealers.
DPF EGR SCR & DEF Browse Cummins codes
