Ignition Systems With C-4 Emissions: Description

Many General Motors vehicles are equipped with the C-4 Emissions System (Computer-Controlled Catalytic Converter). Although basically an electronically-controlled emissions system, the C-4 also provides a self-diagnosis system affecting the ignition system.

Components include a 3-way catalytic converter, an exhaust gas oxygen sensor, an electronic control module, an electronically-controlled air/fuel ratio carburetor and other optional sensor-type components which supply information to the electronic control module.