On-board diagnostics for electronic emission control systems

Use of microcomputer electronics in the automobile in large volume for drivetrain control will require corresponding changes in automotive service methodology. To make this introduction as transparent as possible, the General Motors (EM) electronic control system will include integral self-test and diagnostic aids. These features were addressed throughout the emission control systems (ECS) concept, design and develoJ;ment phases, using the same system engineering techniques applied to achieving control functions. The ECS will include fail-operational redundancy and control software, self-test hardware, diagnostic fault isolation and self-test software, and diagnostic service aid software. The effectiveness of these features in the field will be closely monitored through a multi-divisional service structure, and data continually fed back to subsequent systems to achieve the maintainability level required of automotive transportation. Concepting and implementing of on-board diagnostics for the electronic ECS has been a top-down effort involving nunerous GM division and staff areas. Any attempt to identify unique contributors would be almost as difficult as the task itself.