C 2500 Truck 2WD V8-350 5.7L (1988)
Electric Air Control Valve: Description and Operation
The ECM energizes an AIR CONTROL solenoid. This allows air to flow to an AIR SWITCHING valve. When the engine is cold, the air switching
valve is energized to direct air to the exhaust ports.
On a warm engine when in closed loop, the ECM deenergizes the air switching valve, directing air to the dual-bed converter.
On some engines during deceleration, the air is diverted to the air cleaner or the converter depending on the application. Others do not divert during
deceleration. Also, under an enrichment condition or when the ECM has recognized a failure in the system and set a code, the ECM will cause the air to
be diverted to the air cleaner or atmosphere depending on the application. If the system senses a lean condition for too long, air will be diverted to the
air cleaner. When coolant temperature is below a specified value, air will divert to the air cleaner.
