Automatic Vehicle Diagnostic Systems

With the increasing emphasis on vehicle safety and proper engine performance to assure low levels of exhaust emissions, automatic diagnostic systems will be required to service the large vehicle population in use. Techniques are described which use a combination of on-vehicle and off-vehicle sensors and equipment to check the condition of engine, drive train, brake, steering, and suspension components. The tradeoff considerations for selecting on-vehicle versus off-vehicle sensors are discussed, and types of testing which can be practically implemented are outlined.

In addition, the use of results from vehicle handling and brake-system component degradation studies for establishing limits of acceptable performance for automatic diagnostic testing are presented.