Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Electric Air Control Valve: Description and Operation
This system helps reduce hydrocarbon (HC) and carbon monoxide (CO) exhaust emissions. It also heats the catalyst and oxygen sensor quickly
during engine warm-up. This is accomplished by injecting air into the exhaust port or catalytic converter.
When the ECM energizes the air control valve, air is allowed to flow to the air switching valve. The air switching valve then directs this air to the
exhaust port.
During warm engine operation (closed loop), the ECM deenergizes the air control valve. This causes the air switching valve to direct air to the
catalytic converter.
If the air control valve detects a rapid increase in manifold vacuum (deceleration condition), or ECM detects any failure in the CCC system, air is
diverted to the air cleaner or is dumped to the atmosphere.
