DTC P0410: Secondary Air Injection System: Description

The secondary Air Injection (AIR) system is designed to lower exhaust emission levels on engine start up. The AIR pump runs for approximately 1 minute or until Closed Loop is attained.

The Powertrain Control Module (PCM) commands the AIR pump relay ON by supplying a ground on the relay control circuit. This action energizes the AIR pump, forcing air into the exhaust stream. The PCM also commands the AIR vacuum control solenoid valve ON, which applies engine vacuum to the AIR shut-off valve. When vacuum is applied to the AIR shut-off valve, airflow from the AIR pump flows through the pipes/hoses to the exhaust check valves. The air then enters the exhaust stream. The air that is introduced into the exhaust system decreases the time it takes for the convertor to begin its process of converting the incomplete gases; reducing exhaust emission levels. When inactive, the check valves and the shut-off valve prevent airflow in either direction.

The PCM detects a system airflow problem by monitoring the Heated Oxygen Sensors (HO2S) and Short Term Fuel Trim during normal AIR system operation. This is called a passive test. If the passive test indicates a pass, the PCM takes no further action. If the passive test fails or is inconclusive, the diagnostic will proceed with an intrusive or active test. The PCM will command the AIR system ON during closed loop operation under normal operating conditions. The active test will pass or fail based on the response from the HO2S. A lean HO2S response indicates that the secondary AIR system is functioning normally. An increasing Short Term Fuel Trim value also indicates a normally functioning system. The AIR diagnostic consists of the passive test and the active tests. The AIR diagnostic requires failure of the passive and active tests on 2 consecutive key cycles to illuminate the MIL and store a DTC. If the PCM detects that the HO2S and Short Term FT did not respond as expected on one of the engine banks, DTC P0491 or P0492 sets. If the PCM detects that the HO2S and Short Term FT did not respond as expected on both of the engine banks, DTC P0410 sets.