CCC Theory/Operation: Description: Notes

NOTE: Most Computer Command Control (CCC) problems are the result of mechanical breakdowns, poor electrical connections, or damaged vacuum hoses. Before considering the CCC system as a possible cause of problems, check ignition high tension wires, fuel supply, electrical connections, and vacuum hoses. Failure to do so may result in lost diagnostic time.

The computerized engine control system used on 1988 General Motors trucks monitors as many as 19 engine/vehicle functions. Refer to ECM CONDITIONS SENSED & SYSTEMS CONTROLLED in this article. This system controls engine operation and lowers exhaust emissions while maintaining fuel economy and driveability. The Electronic Control Module (ECM) is the "brain"of the CCC system.

The computerized engine control system is primarily an emission control system, designed to maintain a 14.7:1 air/fuel ratio under all operating conditions. When the ideal air/fuel ratio is maintained, the 3-way catalytic converter can control Oxides of Nitrogen (NOx), Hydrocarbon (HC) and Carbon Monoxide (CO) emissions.