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
The air pump air injection system is designed to reduce hydrocarbon (HC) and carbon monoxide (CO) content of exhaust gases by injecting a controlled amount of compressed air into the exhaust manifold.
System components and application vary among models. Components of system are a belt-driven air pump with integral relief valve, air control valve with 2 relief valves, air switching valve (except B2000), 2 water thermo valves (1 on B2000; 1 water thermo valve and 1 water thermo switch on 626), vacuum delay valve, check valve (except B2000), secondary air check valve, 3-way solenoid valve, air injection nozzle (626 and B2000), catalytic converters (1 on B2000) and various hoses and piping. A heat hazard warning system is used on GLC Wagon and 626 models to prevent exhaust system overheating.
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.