How to Replace a Secondary Air Injection Pump

The air injection system introduces oxygen into the exhaust engine at certain times to reduce emissions. Typical system components include the PCM, air injection relay, air injection hoses, valves and the pump. The air injection pump can be either belt driven or electric - for this article, we will focus on the belt-driven design.

The air injection pump is the focal point of the system. Air enters the pump and it is then directed to the desired location by PCM controlled valves. During engine warm up, the air is directed to the exhaust manifold. Then, in most systems, the air is directed to the catalytic converter once the engine reaches the optimum operating temperature.

Problems with the air injection system can result in increased emissions and engine performance issues. Typically, the Check Engine Light will be illuminated and diagnostic trouble codes (DTCs) will be stored in the PCM.

Part 1 of 2: Remove the air injection pump

Materials Needed

locating the air injection pump

Step 1: Locate the air injection pump. The air pump is at the front of the engine with the serpentine belt wrapped around it.

  • Tip: Make sure there is a belt routing diagram under the hood of your car so you know how to reinstall the belt. If not, take a picture of the belt routing with your phone before proceeding further.

removing the serpentine belt

Step 2: Remove the serpentine belt. Remove the serpentine belt by inserting a ratchet end into the square slot on the tensioner.

Push the tensioner away from the belt and slide the belt off the pulleys.

  • Note: Some older vehicles use a v-belt instead of a serpentine belt. In this case, loosen the pump mounting bolts and the adjustment bracket. Then, move the pump inboard until the belt can be removed.

removing the hoses from the pump

Step 3: Remove the hose. Undo any clamps and slide the hose off the connection and remove it from the pump.

removing the electrical connector from the pump

Step 4: Remove vacuum lines and electrical connections. Remove any vacuum lines and electrical connections from the pump, if any.

removing the pump mounting bolts

Step 5: Remove the air pump mounting bolts. Remove the air pump mounting bolts using a ratchet or wrench.

removing the pump

Step 6: Remove the air pump. Remove the air pump from the vehicle.

Part 2 of 2: Install the new air pump

installing the new air pump

Step 1: Install the new smog pump. Lower the new smog pump into the vehicle and slide it into position.

reinstalling the bolts

Step 2: Tighten the mounting bolts. Reinstall the smog pump mounting bolts and tighten them down until they are snug.

Step 3: Put back the electrical connections. Reinstall the vacuum lines and electrical connections, if any.

reinstalling the hoses

Step 4: Reinstall the air pump hoses. Slide the hose back over the pump connection and tighten down any clamps.

reinstalling the serpentine belt

Step 5: Reinstall the serpentine belt. Reinstall the serpentine belt by pushing on the tensioner so that the belt can be slid over the pulleys.

  • Tip: Consult the underhood belt routing diagram if needed or refer to the photos that you took earlier.

  • Note: If you have an older vehicle with a v-belt, move the pump outboard so the belt can be installed. Then, tighten down the pump mounting bolts and adjustment bracket.

If you prefer to have a professional install the new air pump for you, get a certified technician from YourMechanic to perform the air pump replacement for you.


Next Step

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Recent Car Air Pump Replacement reviews

Excellent Rating

(42)

Rating Summary
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39
2
1
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Raymond

27 years of experience
127 reviews
Raymond
27 years of experience
Mercedes-Benz ML500 - Air Pump - Apple Valley, California
Raymond is a great mechanic. I’m divorced and I have several cars so having a mechanic that I can trust makes all the difference in the world. I definitely have recommend him and I will keep recommending him
Mercedes-Benz CLS500 - Air Pump - Apple Valley, California
Raymond is awesome. Very knowledgeable in his work. And an overall great guy. Thank you, Raymond.

Chris

22 years of experience
2024 reviews
Chris
22 years of experience
Mercedes-Benz E320 - Air Pump - Orange, California
Chris was early, and fixed the issue. He ran into some issues due to my car being 24 years old, and he was able to work around it. Would use again, and would recommend
Toyota Sequoia - Air Pump - Santa Ana, California
Top notch experience. Chris did a great job.

Scott

36 years of experience
802 reviews
Scott
36 years of experience
Cadillac Eldorado - Air Pump - Mesa, Arizona
A difficult job the local garage could not do - I should have called on Scott first as I knew he could do it and he did.
Volkswagen Passat - Air Pump - Mesa, Arizona
Highly trustworthy and excellent service. Dedicated inspections on related parts were awesome. Two thumbs up.

Samuel

11 years of experience
16 reviews
Samuel
11 years of experience
Mercedes-Benz S550 - Air Pump - Locust Grove, Georgia
Great Service, very professional and thorough. Better than my expectations and quicker than I thought. Very Knowledgeable. Would use again.

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