Certain vehicles may be equipped with a secondary air injection (AIR) system. The AIR system lowers the tail pipe emissions on start-up. The PCM grounds the AIR pump relay control circuit, which energizes the AIR pump. The PCM also grounds the AIR solenoid valve control circuit, which energizes the AIR solenoid valve. The AIR solenoid valve opens allowing a manifold vacuum to open the AIR control valves. The PCM enables both control circuits when AIR system operation is desired. When the AIR system is active, the AIR pump forces fresh air into the exhaust stream which accelerates the catalyst operation. The AIR control valves replace the conventional check valves. When the AIR system is inactive, the AIR control valves prevent any air flow in either direction.

A DTC P0412 applies to the AIR solenoid control circuit. A DTC P0418 applies to the AIR pump relay control circuit. A DTC P0410 sets if an air flow problem is detected.

If no air flow enters the exhaust stream, HC and CO emission levels will be too high.

Air flowing at all times could increase the warm-up temperature of the 3-way catalytic converter.

The AIR pump is an electric regenerative turbine type which is permanently lubricated and requires no periodic maintenance.

The engine should be at a normal operating temperature in Neutral at idle. Monitor the HO2S 1 on the scan tool. Use the scan tool to enable the AIR system. The HO2S voltage should remain less than 350 mV because air is being added to the exhaust. If the HO2S voltage remains low during the Output Test, the AIR pump, the AIR solenoid valve, and the AIR control valves are operating satisfactorily.

Refer to the appropriate DTCs for diagnosis of the AIR system.

Inspect all AIR system pipes and hoses for the following: