OBD-II
Workshop glossary › Diagnostics & protocols · UpdatedThe on-board diagnostics standard required on most cars sold in the US since 1996 and in the EU since 2001 (as EOBD). It defines how external tools read fault codes and live data from a vehicle.
OBD-II is the second generation of on-board diagnostics. Every car sold in the United States since model year 1996 has to support it, and the European Union mandated the same set of services for petrol cars from 2001 and diesel from 2004 under the name EOBD. It is the reason a workshop can plug one scan tool into a 16-pin connector and pull data from any modern vehicle.
The standard covers four things: the physical connector and pinout (SAE J1962), the underlying transport (CAN-bus via ISO 15765-4 on every car built after 2008), the service modes (SAE J1979), and the format of fault codes (SAE J2012). What it does not cover are the manufacturer-specific parameters and bidirectional controls — those live behind UDS or KWP2000 protocols and need a brand-aware tool.
For shop-floor purposes: any OBD-II scanner will read generic powertrain DTCs (the P0xxx range), MIL status, freeze-frame data, readiness monitors, and a fixed list of live PIDs. That is enough to triage 80% of check-engine-light jobs before a deeper tool is needed.