Secondary Air Injection System Monitor - Electric Secondary Air Injection Pump System

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Secondary Air Injection (AIR) system monitor is an on-board strategy designed to monitor proper function of secondary air injection system. AIR monitor for electric secondary air injection pump system consists of 2 monitor circuits: an AIR circuit to diagnose concerns with primary circuit side of Solid State Relay (SSR), and an AIR Monitor circuit to diagnose concerns with secondary circuit side of SSR. A functional check is also performed that tests ability of AIR system to inject air into exhaust. Functional check relies upon HO2S sensor feedback to determine presence of air flow. The monitor is enabled during AIR system operation and only after certain base engine conditions are first satisfied. Input is required from ECT, IAT, and CKP sensors and HO2S monitor test must also have passed without a fault detection to enable AIR monitor. AIR monitor is also activated during KOER self-test.

The AIR circuit is normally held high through AIR bypass solenoid and SSR when output driver is off. Therefore a low AIR circuit indicates a driver is always on and a high circuit indicates an open in PCM. DTC P0412 is associated with this test.
The AIR Monitor circuit is held low by resistance path through AIR pump when pump is off. If AIR monitor circuit is high, there is either an open circuit to PCM from pump, or there is power supplied to AIR Pump. If AIR monitor is low when pump is commanded ON, there is either an open circuit from SSR or SSR has failed to supply power to pump. DTCs P1413 and P1414 are associated with this test.
The functional check may be done in 2 parts: at start-up when AIR pump is normally commanded ON, or during a hot idle if start-up test was not able to be performed. The flow test relies upon HO2S to detect presence of additional air in exhaust when introduced by secondary air injection system. DTC P0411 is associated with this test.
MIL is activated after one of the above tests fail on 2 consecutive drive cycles.