6 Symptoms of a Bad Secondary Air Injection Pump & Replacement Cost

bad secondary air pump symptoms

I was on my way to work when I noticed that my secondary air injection pump was bad. I didn’t think much of it at first, but the car started making a strange noise and began to smoke.

I pulled over to the side of the road and called a tow truck. I was worried that the exhaust manifold would blow up while driving it, so I was glad to get it off the road. The tow truck driver said that he had seen this before and told me that it would be cheaper to fix the pump than buy a new car.

He wasn’t kidding – the repair bill came out to nearly $1,000! But at least my car was now running smoothly again. But this is when I realized the importance of an air pump.

This article is all about the symptoms of a failing secondary air system and how to diagnose it.

What is the Function of Secondary Air Injection Pump?

The Secondary Air Injection Pump is a small device located on or near your car’s exhaust system. It takes in ambient air from the atmosphere. It mixes it with fuel that comes out of the engine before entering the internal combustion engine, where the combustion process occurs at high temperatures over 500 degrees Fahrenheit (260 C).

This process helps reduce nitrogen oxide emissions harmful to human health and contributes to global warming. This system aims to inject oxygen into your exhaust stream during cold starts and at low speeds.

The water vapor in fresh air creates a foam-like substance in the exhaust manifold, which grabs all the bad pollutants and takes them away from the catalytic converter. This keeps car’s emission clean and healthy to run on roads.

This helps the catalytic converter to start working more effectively. This also aids in preventing air pollution and allows for better fuel economy since fewer pollutants are being emitted from your exhaust manifold.

I know this sounds like a lot of work, but don’t worry – most cars today have these pumps as standard equipment, so it’s not something you’ll need to worry about unless your vehicle is older than 1990 or if you drive an exotic car like a Ferrari.

Symptoms of Bad Secondary Air Injection System

Following are the most common symptoms of a bad secondary air system.

  1. Check Engine Light
  2. Failed Catalytic Converter
  3. Failed Emissions Test
  4. Low Idle
  5. Sluggish Acceleration
  6. Engine Stalls

Let us look at the signs of a bad air injection smog pump.

1. Check Engine Light

One of the most common symptoms of a bad secondary air system is that the Check Engine Light will come on. This light comes on when there is a problem with the engine, and it can be triggered by a variety of issues, including a failing secondary air injection pump.

If your car has this light on, take it to a mechanic as soon as possible to have it checked out. Failing to address the problem could result in more severe damage to your car.

2. Failed Catalytic Converter

If your secondary air injection pump has failed, you may notice that the catalytic converter is not working as well as it should. This problem can lead to a loss in power and performance from your engine.

The catalytic converter is the engine’s first line of defense against harmful emissions. The air injection system helps keep it clean by injecting oxygen into the exhaust stream, which helps get rid of carbon monoxide and other pollutants before they can enter your car’s cabin or cause an explosion in your garage!

When the catalytic converter is not working properly, you will notice a decrease in fuel efficiency because of increased exhaust flow resistance, which increases engine operating temperatures.

If you’re experiencing any of these problems, it’s best to take your car in for a diagnostic test of tailpipe emissions to see if the catalytic converter is at fault.

3. Failed Emissions Test

When your air injection smog pump fails, the emissions test will fail. The car’s catalytic converter converts harmful gases into less harmful ones.

It does this by oxidizing carbon monoxide, hydrocarbons, and nitrogen oxides with oxygen from the air injection system before they can enter your exhaust stream or cause an explosion in your garage! When there isn’t enough injected oxygen to do its job properly, these gases remain in higher concentrations than normal.

A failed emissions test signifies that something isn’t right with your air injection system. The problem could be anything from a faulty pump to an issue with the fuel injectors themselves, so it’s important for any mechanic who works on cars regularly should know about this symptom!

4. Low Idle

If your car has a low idle, it’s most likely due to a problem with the air pump. When this pump fails, it can’t provide enough oxygen to the catalytic converter, which causes the engine to stall or run very slowly.

5. Sluggish Acceleration

If your car is sluggish when you try to accelerate, it’s likely because of a failing secondary air injection pump. You may also notice that your car doesn’t seem as powerful as it used to be. This is because a bad air injection pump can’t provide the engine with enough oxygen to function at its best.

If you’re experiencing any of these symptoms, it’s important to take your car in for a diagnostic test as soon as possible! The sooner you address the problem, the less damage it will do to your car’s engine and catalytic converter.

6. Engine Stalls

Symptoms of a bad secondary air injection pump or SAS pump are an engine that stalls or runs rough when idling. This happens because the SAS System may not maintain idle speed when it fails, partially closing the throttle plate to maintain RPMs.

It then becomes apparent when you’re stopped at a traffic light or in a store parking lot that if your engine stalls while idling, the secondary air injection system may be the culprit.

How to Diagnose a Bad Secondary Air Injection Pump?

If you’re experiencing any of the symptoms described above, it’s important to take your car in for a diagnostic test. There are a few things that a mechanic will look for when trying to diagnose a bad air injection pump:

1. Check Combination Valve & Control Relay.

Combination valve failure can cause a secondary air injection pump to overheat and stop functioning. It may also lead to the illumination of Malfunction Indicator Lamp (MIL) on the control panel. The combination valve helps divert excessive amounts of unburned oxygen into the exhaust system during engine load demand. If it is faulty, there will be no airflow to the pump. This will cause it to overheat.

2. Perform Acoustic Check.

Another way of diagnosing a bad secondary air injection pump is to perform an acoustic test. The acoustic test will produce a sound that sounds similar to a coffee grinder running in the background of your engine. You may have to rev your engine to hear it well during this exercise. If you do not hear the sound, it can mean that your pump is bad.

3. Check Control Valve and Hose Fittings.

The control valve on the secondary air injection system aids in regulating the amount of secondary air fed into your exhaust. However, if you have faulty hose fittings, it will cause an over-supply of unburned oxygen to enter your exhaust system, leading to overheating of the pump. You may also notice a clear loss of power and excessive exhaust emissions.

4. Check the Fuel Tank Pressure Relief Valve.

A faulty pressure relief valve can cause a secondary air injection pump to malfunction, usually, this is caused by it getting clogged with rust or debris on the diaphragm that is responsible for regulating pressure on your fuel tank. This may also be accompanied by a noticeable lack of power and trouble restarting your engine, as well as the illumination of the MIL on your control panel.

5. Perform Actuator Test

While the secondary air injection pump itself is a very reliable part, some other procedures can cause it to overheat and malfunction. One is due to the failure of the actuator on your throttle body. If this part fails, then you may experience trouble with starting your engine as well as a drop in your fuel economy or power output.

Replacement Cost of Secondary Air Injection Pump

The average price range for most models lies between $300-$500 and can be higher for luxury vehicles like Mercedes Benz or BMWs.

The replacement cost of a secondary air injection pump depends on the make and model of your car. It also depends on whether you choose to take it in for repair at an independent automotive shop or at a dealership and how much labor is involved with replacing this part.

The best way to get a quote on this repair is by calling an ASE-certified mechanic who will inspect your vehicle before giving you an estimate of the work required, with labor costs included. This will help prevent any potential surprises down the road due to unknown issues.


The engine control unit with an air pump reduces emissions, should your engine need a little help in that department. If you’re driving around with your SAI pump locked up, then you’re not doing anyone (least of all yourself) any favors and maybe causing some damage to your engine. A seized-up SAS can cause quite a few issues, even if they are only temporary.

All of that is an indirect consequence of your car not meeting emissions regulations. Maybe you missed that notice on the door from the EPA inspector telling you to get the pump replaced asap?

If you’re not worried about your car continuing to pass inspection, then that’s a different story.

In that case, you may as well remove the air pump from your car and start saving for something newer. All jokes aside, if you’re going to do this, make sure you have a plan to bypass the system permanently before performing any irreversible modifications.

Either way – Fix it or forget it, It’s up to you.

Frequently Asked Questions

Can you drive without a secondary air pump?

Yes, you can drive without a secondary air pump for some time. But to do this, your car needs to be over 15 years old. It must pass the annual tailpipe test mandated by law in all states of the US except California, where these rules only apply when changing ownership or moving across state lines with new registration requirements (which means not every vehicle will meet all requirements).

If you do not have an air pump, there is no oxygen getting into your exhaust system, which means that it won’t burn any fuel. This results in very high levels of carbon monoxide emissions from the tailpipe and could potentially damage other engine components due to excessive heat.

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