Feedback Carburetor Tests W/Codes: Description

This article includes test information for Code Tests only. For information on symptom tests, refer to the FEEDBACK CARBURETOR SYMPTOM TESTS article in this section. For information on component tests, refer to the FEEDBACK CARBURETOR COMPONENT TESTS article in this section.

The Computer Command Control (CCC) system controls engine operation and lowers exhaust emissions while maintaining good fuel economy and driveability. The Electronic Control Module (ECM) is the "brain" of the CCC system. The ECM controls as many as 12 engine related systems constantly adjusting engine operation.

The CCC 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 catalytic converter can control oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO) emissions.

Fig 1: ECM Operating Conditions Sensed & Systems Controlled

Fig 2: Sectional View of Mixture Control (M/C) Solenoid Note air bleed above main metering rod.

Fig 3: Component Locations for "S" Series Trucks

Fig 4: Component Locations for "G" Series Trucks With 4.1L Engine

Fig 5: Component Locations for "G" Series Trucks With V8 Engines

Fig 6: Component Locations for "C/K" Trucks With 4.1L Engine