Circuit/System Description

The secondary air injection 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. Ignition voltage is supplied directly to the secondary air injection pump relay and secondary air solenoid valve relay. The engine control module (ECM) controls the relays by grounding the control circuit with a solid state device called a driver. The ECM monitors the control circuits for open, short to ground or short to voltage conditions.