OBD-II PIDs

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OBD-II PIDs (On-board diagnostics Parameter IDs) are codes used to request data from a vehicle, used as a diagnostic tool.

SAE standard J1979 defines many OBD-II PIDs. All on-road vehicles and trucks sold in North America are required to support a subset of these codes, primarily for state mandated emissions inspections. Manufacturers also define additional PIDs specific to their vehicles. Though not mandated, many motorcycles also support OBD-II PIDs.

In 1996, light duty vehicles (less than 8,500 lb or 3,900 kg) were the first to be mandated followed by medium duty vehicles (8,500–14,000 lb or 3,900–6,400 kg) in 2005.^[1] They are both required to be accessed through a standardized data link connector defined by SAE J1962.

Heavy duty vehicles (greater than 14,000 lb or 6,400 kg) made after 2010,^[1] for sale in the US are allowed to support OBD-II diagnostics through SAE standard J1939-13 (a round diagnostic connector) according to CARB in title 13 CCR 1971.1. Some heavy duty trucks in North America use the SAE J1962 OBD-II diagnostic connector that is common with passenger cars, notably Mack and Volvo Trucks, however they use 29 bit CAN identifiers (unlike 11 bit headers used by passenger cars).