Circuit Description

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The secondary air injection (AIR) system is designed to reduce exhaust emissions after initial engine start-up. This occurs when coolant start up temperature and intake air temperature (IAT) are at the conditions listed below. The AIR pump will operate for less than 25 seconds. The powertrain control module (PCM) commands the AIR system ON by simultaneously supplying a ground to the AIR pump relay and the AIR solenoid relay. When commanded ON the AIR pump forces fresh air through the electronic shut-off valve and into the exhaust manifold, accelerating catalyst operation. When the AIR system is inactive, the electronic shut-off valve prevents airflow in both directions. The PCM will run the AIR diagnostic passive test only on ignition cycles when the pump is commanded ON. If this test passes, then no active test will run. If the passive test fails, or is inconclusive, the active test will run later in the ignition cycle. At that time the PCM runs a maximum of two 3 second active tests, monitoring the heated oxygen sensor (HO2S) 1 voltage, expecting a drop below 150 mV. When the PCM detects an insufficient HO2S 1 response, DTC P0410 will set.