This document supersedes SAE J2012 DEC2007, and is technically equivalent to ISO 15031-6:2010 with the exceptions described in 1.2.

This document is intended to define the standardized Diagnostic Trouble Codes (DTC) that On-Board Diagnostic (OBD) systems in vehicles are required to report when malfunctions are detected. SAE J2012 may also be used for decoding of enhanced diagnostic DTCs and specifies the ranges reserved for vehicle manufacturer specific usage.