Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Air Injection: Description: Description
Partial zero emission vehicles (PZEV) are equipped with a 2.4L engine with air injection. The air injection system injects air into the exhaust to reduce the emissions during engine warm-up. The air injected into the exhaust will cause the catalytic converter to heat up more quickly. This will improve the emission levels during a cold start. The system consists of an air pump (3), mass air flow sensor (4) and a vacuum check valve (1). The powertrain control module (PCM) controls air pump operation through the air pump relay.
The air injection pump (3) is located in the rear of the engine compartment. The pump is operated by an internal electrical motor and is mounted to a bracket by rubber isolators. An inlet air hose and outlet connecting tube (2) are attached to the air pump.
A mass air flow (MAF) sensor (4) measures the air flow through the air supply hose and works in conjunction with the one way check valve (1). The valve controls the air that is supplied to the exhaust manifold.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.