Emission Control Systems: Testing and Inspection

To ensure proper operation of all emission control system components it is necessary to perform a visual inspection.

Refer to the Vehicle Emission Control Information Label and the Emission Control Application Charts for emission control component installation. During this inspection, vacuum hoses should be checked for condition and proper connections. Vacuum hoses should be free of pinches, cuts, cracks and disconnects. In areas where hoses are difficult to view, an inspection mirror may be required. Emission control vacuum hose routing should be confirmed by referring to the vacuum hose routing on the Vehicle Emission Control Information or Vacuum Hose Routing Label, which should be affixed in the vehicle's engine compartment. If a vacuum hose routing modification has been authorized by the vehicle manufacturer, an Emission Control Modification Label should be affixed to the engine compartment noting this change. Any other modifications to the vacuum hose routing should be considered suspect.

Engine compartment wiring harnesses should be checked for proper routing and loose or disconnected electrical connectors. Wiring should also be checked for burned or chaffed insulation. Also ensure wiring is not in contact with sharp edges, exhaust manifolds or in places where wiring may be pinched. Check ignition wiring for heat damage and deterioration. Also note condition of distributor cap.

Inspect for unauthorized modifications to the fuel system. On models with exhaust gas recirculation, ensure all components are properly connected. While viewing underhood area with engine operating, inspect for engine misfire, unstable idle speed and abnormal noises. Also note any fuel, coolant engine oil, vacuum, exhaust or compression leaks, as these may effect engine or emission control system operation.

Check exhaust system for deterioration, damage and exhaust leaks. On models which require a catalytic converter, ensure catalytic converter is in place. Also inspect for unauthorized modifications. On models with catalytic converter, ensure fuel restrictor in fuel tank filler neck is in place.

When in passenger compartment of vehicle, check instrument panel for any illuminated Check Engine, Power Loss or Emission Reminder indicator lamps. Illumination of these lamps could be an indication of a malfunctioning or inoperative emission control or related system.