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 System: Description
The air injection system reduces Hydrocarbon (HC) and Carbon Monoxide (CO) emissions by supplying filtered air to exhaust manifold. On Pulsar NX and Sentra, the system consists of an air temperature sensor, air injection control solenoid valve, air injection valve, air cleaner and water temperature sensor. The Electronic Control Unit (ECU) coordinates function of the air injection valve. On Pulsar NX SE, the system consists of an air injection valve, air temperature sensor, coolant temperature sensor and thermal vacuum valve.
On Maxima and 200SX SE, system includes an air injection valve, air injection control solenoid valve, pressure regulator control solenoid valve, water temperature sensor and Electronic Concentrated Engine Control System (ECCS) control unit. The air injection valve is controlled by the ECCS control unit, corresponding to engine temperature.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.