CCC Theory/Operation: Description

NOTE: Most CCC problems are result of mechanical breakdowns, poor electrical connections, or damaged vacuum hoses. Ignition high tension wires, fuel supply, electrical connections and vacuum hoses should be checked before CCC. Failure to do so will result in wasted time.

NOTE: This system is also covered in the FUEL SYSTEMS section. Additional information on only the fuel portion of this system can be found in the ELECTRONIC FUEL INJECTION articles in the FUEL SYSTEMS section.

NOTE: This article refers to models by body style. "T" bodies - Chevette and T1000; "X" bodies - Citation, Omega, Phoenix and Skylark; "A" bodies - Century, Celebrity, Ciera and 6000; "F" bodies - Camaro and Firebird; "J" bodies - Cavalier, Cimmaron, Firenza, J2000 and Skyhawk.

Fig 1: Schematic of Computer Command Control System

The Computer Command Control (CCC) system is a system used on all General Motors gasoline engines (except Cadillac with DFI). It monitors up to 15 engine/vehicle functions. It controls engine operation and lower exhaust emissions while maintaining good fuel economy and driveability. The Electronic Control Module (ECM) is the "brain" of the CCC system. The ECM can control as many as 9 engine-related systems to constantly adjust engine operation.

The CCC system is primarily an emission control system, designed to maintain a 14.7:1 air/fuel ratio under all conditions. When an ideal ratio is maintained, the catalytic converter can control nitrogen oxides (NOx), hydrocarbons (HC) and carbon monoxide (CO).

Three basic versions of the CCC system are used. The Minimum Function system controls the fuel and air management systems only. The Full Function system adds control of ignition system, torque converter clutch and emission controls. The EFI system is similar to the Full Function system except that it controls fuel injection instead of a carburetor.