This document supersedes SAE J2012 APR2002, and is technically equivalent to ISO 15031-6:2005 with the exceptions described in Section 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. This document includes:

1. a Diagnostic Trouble Code format.
2. b A standardized set of Diagnostic Trouble Codes and descriptions
3. c A standardized set of Diagnostic Trouble Codes subtypes known as Failure Types