Introduction to On Board Diagnostics (II)

OBD II for L & MD VehiclesDiagnostic Trouble Codes (SAE J 2012):STD ManualData Link Security (SAE J 2186):SAE J 2186 defines the security practices that must be implemented ed in accessing Diagnosticinformation only by authorized persons. The standard defines several eral levels of accessibility, likesecured functions, unsecured functions, and read only data. The emission related data isaccessible only to authorized personnel from EPA, responsible to ensure that the standard iscomplied with.Computer-coded engine operating parameters shall not be changeable without t the use ofspecialized tools and procedures accessible to only authorized persons. pAny reprogrammable computer code shall employ proven methods to deter unauthorizedreprogramming.CARB and EPA require that enhanced tampering protection for the 1999 model year that shallinclude data encryption and electronic access to manufacturer computer for security access.Procedure is defined to provide legislated “tamper protection”, while meeting manufacturerdesired security concerns for tamper resistance and allowing legitimate service.One such technique enables certain operations such as Block download only if security access issuccessful. Normal communications are not affected.