Skip the auto shop - Our mechanics make house calls

How to Replace an Air Injection Pump Filter

overheating engine with person next to it

The air injection system introduces oxygen into the exhaust to reduce emissions. The system consists of a pump (either electric or belt driven), pump filter, and valves. Intake air enters the pump through a centrifugal filter located behind the drive pulley. When the engine is cold, the powertrain control module (PCM) controls the diverter valve to send pumped air to the exhaust manifolds. After the engine has reached operating temperature, it diverts air to the catalytic converter.

Your air pump filter may be failing when the engine is functioning sluggishly and there is a noticeable dip in performance. You may also notice poorer fuel economy and a rougher idle overall, since the air pump filter cannot adequately provide airflow to the engine. If these symptoms appear, you may need a new air pump filter.

Part 1 of 2: Remove the old filter

Materials Needed

  • Needle-nose pliers
  • Protective gloves
  • Ratchet
  • Repair manuals
  • Safety glasses
  • Wrench

  • Note: Be sure to put on safety glasses and protective gloves to keep from injuring yourself during the replacement process.

loosening the smog pump pulley bolt with a wrench

Step 1: Loosen the air pump pulley. Loosen the smog pump pulley retaining bolts with a socket or wrench.

removing the serpentine belt

Step 2: Remove the serpentine belt. Make sure there is a belt routing diagram under the hood of your car or take a picture of the belt with your phone prior to removal.

This way, you will know how to reinstall the belt. Remove the serpentine belt by inserting a ratchet end into the square slot on the tensioner or by placing a socket on the pulley bolt head. Push the tensioner away from the belt and slide the belt off the pulleys.

  • Note: Some vehicles use a v-belt instead of a serpentine belt. With this set up, you will need to loosen the pump mounting bolts and adjustment bracket. Then, move the pump inward until the belt can be removed.

removing the smog pump pulley by hand

Step 3: Remove the air pump pulley. Remove the pulley retaining bolts completely and slide the pump pulley off the mounting shaft.

removing smog pump filter with needle nose pliers

Step 4: Remove the air pump filter. Remove the air pump filter by grasping it with needle-nose pliers.

Do not pry on it from behind as the pump may be damaged.

Part 2 of 2: Install the new filter

Materials Needed

  • Needle-nose pliers
  • Ratchet
  • Repair manuals
  • Wrench

Step 1: Install the new air pump filter. Place the new pump filter in position on the pump shaft in the reverse of the way you removed it.

Put the pump pulley back on and tighten down the bolts evenly to properly seat the filter.

Step 2: Reinstall the serpentine belt. Reinstall the serpentine by moving the tensioner so that the belt can be slid back on.

Once the belt is in place, let go of the tensioner. Double check belt routing against the diagram you obtained in the first step.

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

Step 3: Tighten the pump pulley bolts. With the belt in place, tighten down the pump pulley bolts completely.

You now have a new, properly functioning air pump filter installed which will be a huge boost to your engine’s performance. If this seems like a job you’d rather leave to professionals, contact one of YourMechanic’s certified technicians, who can come to your home or place of business and perform a replacement.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...

Related questions

Q: Oil drain plug and pan missing after oil change

Hello there, this is a rare accident that can occur when oil changes are performed. In this type of situation, an oil sample is taken and sent off to a facility that can perform an oil analysis. This is done...

Q: A.I.R. pump whistling

The air injection pump is the most common failure of the air injection system on this vehicle. The system would need to be checked to make sure the pump is the cause of the noise. I recommend you have a...

Q: Vehicle scan showed problem with emissions air pump. My air smog pump was filled with liquid

The air pump sucks in outside air in the lower front fender area and the car may have sucked in water while the pump was running. The only way to stop water from entering the air pump is to not...