Air Injection System

WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.

During vehicle cold start, the Air Injection System (AIS) delivers a controlled amount of outside air into the exhaust system, upstream of the catalytic converters, in order to help reduce hydrocarbon and carbon monoxide gas emissions.

The Air Injection System consists of the following components:

Air Injection Pump
Air Injection Pump Relay
Air Injection (Nylon) Tube
Exhaust one-way check valve
Inlet Air Injection Filter
Inlet Air Injection Hose
MAF Sensor

Fig 1: Identifying Air Injection Components
Courtesy of DAIMLERCHRYSLER CORP.

When the Air Injection Pump is activated, air is drawn into the Air Injection System through the Inlet Air Injection Filter. The air is then passed through the MAF Sensor, which monitors the amount of air that enters the Air Injection System. The PCM uses the MAF Sensor information to control Air Pump operation based on feedback from the front O2 sensor. After passing through the MAF Sensor, air travels through the Inlet Air Injection hose, into the Air Pump (where it is compressed), through the Air Injection (Nylon) Tube, past the Exhaust one-way check valve, and into the exhaust system.