Air Injection System: Operation

The air injection system is used to improve catalyst operation when the engine is warming up. Air is injected only if engine coolant temperature is below 108°F (42°C), oil temperature is above 61°F (18°C) and the oxygen sensor is not operating. When these conditions are present, the air injection relay provides power to the air pump clutch and the switch-over valve.

When the switch-over valve is activated, it provides vacuum to open the air injection shut-off valve, allowing air from the pump to pass through the check valve into the exhaust manifold.