What is the connection between OBD and vehicle emissions?
The purpose of the OBD system is to assure proper emission control system operation for the vehicle s lifetime by monitoring emissions-related components and systems for deterioration and malfunction. There are circumstances under which the vehicle computer will detect a system problem before the driver notices a driveability problem. Furthermore, OBD can detect problems that may not be noticeable upon visual inspection because many component failures that impact emissions can be electrical or even chemical in nature. By detecting these emission-related failures and alerting the driver to the need for potential repair, it is hoped that vehicles will be properly repaired before vehicle emissions become a problem. How does OBD inform drivers of problems? When the OBD system determines that a problem exists, a corresponding “Diagnostic Trouble Code” is stored in the computer s memory. The computer also illuminates a dashboard light indicating “Service Engine Soon” or “Check Engine” or dis
