A brief history of OBD

Until the 1990s, the car industry had no standard for diagnostics or emissions data. Each carmaker used its own connector, its own fault codes and its own tools.

The first engine computers reported faults through a lamp on the dashboard, the Check Engine lamp. On many GM cars, a mechanic connected two pins and the lamp flashed each stored code in a manner similar to morse code. Four flashes, a pause and four more flashes was code 44: an oxygen sensor running lean.

CHECK ENGINE

Code 44The oxygen sensor reads a lean mixture.

Without a standard, no single tool could check the emissions controls of every car. In 1990, US emissions law adopted OBD-II: one port, one way to ask for data: the SAE J1979 standard. This standard established a common diagnostics language that cars are expected to speak, and includes a list of standard parameters (PIDs), such as oxygen sensor readings, fuel trim and the status of each emissions monitor.

Cars sold in the US since '96 have OBD-II. In Europe, the related EOBD applies to petrol cars since '01 and diesel cars since '04. Pelican reads the standard PIDs from nearly every car built since.

Carmakers also add their own commands for data that J1979 does not cover, such as battery charge or tire pressure. These commands differ per vehicle. The OBDb was established to document these facts.

The car catalog

Pelican works with thousands of makes and models from around the world. Find yours here to see what Pelican can learn from it.

The car catalog is built on top of the OBDb, the world's largest open database of OBD command definitions. The OBDb exists to document and standardize the commands that cars can answer to, using real-world driving data from apps like Pelican.

SAE J1979, the industry standard for OBD diagnosticsHundreds of established parameters cars are expected to respond to.

The car catalog

All makes

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