The air injection system pumps air to the exhaust gases in the exhaust manifold to further their combustion.
The system consists of a belt driven air pump, an air control valve, a check valve, air injection tubes, and electrical sensors to prevent exhaust manifold overheating.
Check the belt condition and the tension. Check the hose routing for kinks and the hoses for breaks and damage. Check for abnormal sounds from the pump or valves.
Clean the air pump air cleaner every 12,000 miles and replace it every 24,000 miles.