Circuit/System Description

The secondary air injection (AIR) system aids in the reduction of hydrocarbon emissions during a cold start. The electric air pump forces fresh air into the exhaust stream in order to accelerate the catalyst operation. A secondary air injection pressure sensor is used to monitor the air flow from the AIR pump. The Engine Control Module (ECM) supplies 5 V to the 5 V reference circuit and supplies a ground to the low reference circuit. The sensor provides a signal voltage to the ECM relative to the pressure changes within the AIR system.