This is an old document that describes the beginnings of OBD 2.
This should be the primary document that any technician should read and understand when diagnosing an OBD2 system.
OBD 2 has now changed and that change includes OBD2 diagnosis over a CAN system (Controller Area Network).
All modern vehicles will now use CAN for diagnosis and in many circumstances still use serial data for emissions testing.
Many versions of Handheld, Laptop and Tablet versions are available to help in diagnosis. Some are better that others. The professional versions offer a far better description and many more features to help in diagnosis. Professional versions will assemble data in logs and graphs.
Far better software will playback logs and graph the recordings.
OBD2 is generally used for engine diagnosis (petrol or diesel) and very limited for automatic transmission diagnosis.
You learn with practice and recording data.
The direct link to the document at Long Beach City College:
http://www.lbcc.edu/attc/documents/OBD2.pdf
This should be the primary document that any technician should read and understand when diagnosing an OBD2 system.
OBD 2 has now changed and that change includes OBD2 diagnosis over a CAN system (Controller Area Network).
All modern vehicles will now use CAN for diagnosis and in many circumstances still use serial data for emissions testing.
Many versions of Handheld, Laptop and Tablet versions are available to help in diagnosis. Some are better that others. The professional versions offer a far better description and many more features to help in diagnosis. Professional versions will assemble data in logs and graphs.
Far better software will playback logs and graph the recordings.
OBD2 is generally used for engine diagnosis (petrol or diesel) and very limited for automatic transmission diagnosis.
You learn with practice and recording data.
The direct link to the document at Long Beach City College:
http://www.lbcc.edu/attc/documents/OBD2.pdf