Closed Loop Emission Control System

Closed loop emission control is a system that precisely controls air/fuel ratio, allowing use of a 3-way catalyst to reduce oxides of nitrogen, hydrocarbons and carbon monoxide.

The major components are: oxygen sensor, electronic control module (ECM), controlled air/fuel ratio carburetor, and 3-way catalytic converter. This system utilizes a dasboard mounted malfunction indicator light which, for some failure modes, will inform driver of need for unscheduled maintenance.

In event of system malfunction, "Check Engine" light will come on and remain on as long as fault continues and engine is running. The ECM incorporates a diagnostic program which will assist in diagnosing closed loop control system malfunction. When activated, diagnostic program will flash a code through "Check Engine" light, which isolates source of malfunction.