Description & Operation

Toyota carburetor models use a Feedback Control (FBC) System. By means of a signal from Oxygen (O2) sensor, carburetor primary side main air bleed and slow air bleed volume are controlled to maintain optimum air-fuel mixture. This reduces HC, CO, and NOx in addition to providing better driveability and fuel economy.

All models use an Electronic Air Bleed Control Valve (EBCV). Two vacuum switches are used on Corolla (California) models. See Figure and Figure .

On Corolla California models, Electronic Control Unit (ECU) contains a self-diagnosis system. An instrument panel mounted "CHECK ENGINE" light will flash when a malfunction occurs. ECU analyzes various signals and detects system malfunction. ECU will store failure codes associated with detected failure.