On-Board Diagnostic systems use the vehicle’s computers to detect problems with its emission components and other systems. It informs the vehicle operator when a fault occurs and assists the technicians in identifying and repairing malfunctioning circuits.
There are two different types of On Board Diagnostic systems. OBD 1, which operates under manufacturer standards and OBD 2, which operates under a standard set by the Society of Automotive Engineers.
OBD I is a system that identifies faults in the vehicle’s emission and powertrain.
It has been superseded by OBD II, an enhanced On-Board diagnostic system that identifies faults in the vehicle’s emission and powertrain and also tests the vehicles operational system to determine faults that do not affect the vehicles driveability but may affect its safety or emission efficiency.
Both systems provide a common standard that all vehicle manufacturers adhere to. This means that any generic OBD II compatible scan tool can access most vehicle data.
A scan tool is used to access the on-board diagnostic information, and the data link connector allows for the scanner to be connected to the car. This connector is a common size and shape and its location is also standardized, under the driver’s side of the instrument panel.