1988 The Society of Automotive Engineers (SAE) recommends a standardized diagnostic connector and set of diagnostic test signals. 1994 Motivated by a desire for a state-wide emissions testing program, the CARB issues the OBD-II specification and mandates that it be adopted for all cars sold in California starting in MY1996 (see CCR Title 13 Section 1968.1 and 40 CFR Part 86 Section 86.094). The DTCs and connector suggested by the SAE are incorporated into this specification. 1996 Legislation is passed requiring any component malfunction that causes the MIL to illuminate is the manufacturer's responsibility to repair, provided that the vehicle is within its emissions warranty period. This was done in an effort to persuade manufacturers to produce more robust emissions control equipment. 1998 The OBD-II specification is made mandatory for all cars sold in the United States. 2001 The European Union makes EOBD, a variant of OBD-II, mandatory for all petrol vehicles sold in Europe starting in MY2001 (see European Directive 98/69/EC). 2008 All cars sold in the United States are required to use the ISO15765-4 signalling standard (a variant of the CAN bus).
The AutoXray CodeScout OBD2 scanner will de-mystify that troublesome 'check engine' message and tell you what the problem actually is that triggered it in the first place.