Secondary AIR Injection System Description

Secondary Air Injection System Description


The Secondary Air Injection (AIR) system helps reduce Hydrocarbon (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx) exhaust emissions. It also heats up the warm up 3-way catalytic converters quickly on engine start-up so conversion of exhaust gases can occur sooner.

The system includes the following:
^ AIR pump - The AIR pump is mounted to the lower left front of the engine Compartment and supplies the air to the AIR system. The electric air pump pressurizes fresh air and pumps it to the check valves near the exhaust manifolds. The AIR pump is controlled by the PCM. Battery voltage to the AIR pump is controlled by the AIR pump relay. An integral stop valve prevents air flow through the pump during OFF periods. When the PCM provides a ground circuit for the secondary AIR pump relay, battery voltage is allowed to power up the AIR pump and integral stop valve.
^ Vacuum Bleed Valve - This valve helps prevent vacuum buildup within the AIR system, which could prevent the integral stop valve from opening. The bleed valve is controlled by the air pump relay and is energized when the AIR pump is commanded ON. If the vacuum relief system is not functioning, the vacuum will cause the AIR pump integral stop valve not to open. This may result in no air flow to the exhaust manifolds or delay the delivery of air which may not allow the diagnostic to pass.
^ Check valves - The check valves prevent back flow of exhaust gases into the AIR pump in the event of an exhaust backfire.
^ Necessary plumbing.
- Hoses
- Pipes
- Clamps