Feedback Control Solenoid: Description and Operation

Fig. 39 Operating Conditions For Feedback Control Solenoid Valve:

The feedback control system is designed to provide a stoichiometric air/fuel ratio, allowing the three-way catalytic converter to operate at peak efficiency. The feedback control solenoid valve is provided to stop feedback operation at low engine speed such as idling.
Idle feedback control is handled by air bleed valve B, (located in the air cleaner), and the air leak solenoid valve.