Air Pump Control Valve Buyer’s Guide
- The air pump control valve protects the secondary air injection system while enhancing the effectiveness of the catalytic converter at cleaning the exhaust gas.
- Also called the “air pump check valve,” the air control valve is a one-way valve that manages the air flow into the exhaust system.
- Many engines will feature just one air pump control valve, but a v-type engine may have two check valves. Experts recommend replacing both valves together.
- A vehicle will continue to run even after losing its air pump control valve. However, the exhaust system may release higher levels of toxic emissions that may exceed the limits set by state and federal laws regarding vehicular air pollution.
- Inspect your vehicle’s air pump control valve when you see the check engine light turn on, notice the exhaust resembles dark smog, or learn that your vehicle failed to pass an emissions test.
- You can end up paying anywhere between $35 and $80 for a replacement air pump control valve.
Modern civilization relies on vehicles fitted with internal combustion engines to move both people and cargo. To keep their emission levels at safe levels, today’s fuel-burning vehicles rely on devices and systems like the catalytic converter, the Evaporative Emission Control (EVAP) system, and the secondary air injection (AIR) system. These emission control systems minimize fuel wastage and prevent the release of too much toxic gases into the atmosphere.
A key part of the AIR system is its air pump control valve, an unglamorous but critical component that protects the rest of the emission control system while enhancing the effectiveness of the catalytic converter at cleaning the exhaust gas. This buyer’s guide will cover the details about this valve, including its roles and the symptoms of an old or broken unit that needs replacement.
What Is an Air Pump Control Valve?
Also called the “air pump check valve” in pumped injection-type secondary air injection systems, the air control valve works exactly as its name denotes. It is a one-way valve that manages the air flow into the exhaust system.
Depending on the vehicle’s make and model, either the engine control unit (ECU) or the more complex powertrain control module (PCM) operates the air pump control valve. The computer controls the valve through a solenoid circuit that can switch on or off depending on the conditions inside the exhaust system.
Many engines will feature just one air pump control valve, but a v-type engine may have two check valves. Experts recommend replacing both valves together when one of them triggers an OBD trouble code since the seemingly unaffected unit will probably develop an issue.
What Does an Air Pump Check Valve Do?
The air pump control valve regulates the movement of air in and out of the secondary air injection system. It opens to admit pumped fresh air in the chamber between the engine and the catalytic converter, and the air mixes with the exhaust gases to increase oxygen levels.
Once enough fresh air makes it through the injection point or points, the air pump check valve closes to prevent exhaust gases from entering the AIR system. The gases keep much of the heat they experienced in the engine’s combustion chambers, and their high temperatures can damage the relatively fragile air pump or piping.
The hot exhaust may even reach the vehicle air filter that screens air from the outside for particles that may damage the pump and the rest of the secondary air injection system.
What Does the Secondary Air Injection System Do?
When you start up your car for the first time, the cold engine takes a while to hit peak efficiency. It burns fuel less efficiently and produces more air pollutants like unburned fuel vapor.
To compensate for the initial inefficiency of a cold start, the AIR system adds fresh air to the engine exhaust before the gases go into the catalytic converter. The extra oxygen helps the converter burn potential air pollutants into harmless substances, leading to cleaner exhaust.
The AIR system continues to support the catalytic converter even after the engine gets hot enough to burn fuel. The air pump will only stop working when the vehicle rapidly speeds up because it may otherwise trigger backfiring in the exhaust.
Do You Need a Control Valve for an Air Pump in the Secondary Air Injection System?
A vehicle will continue to run even after losing its air pump control valve. However, it may perform less efficiently than normal, especially during cold starts. The exhaust system may also release higher levels of toxic emissions that may exceed the limits set by state and federal laws regarding vehicular air pollution.
The ECU/PCM monitors the exhaust gas through oxygen sensors placed between the engine and the catalytic converter, as well as another pair of sensors behind the converter. It also tests the various parts of the secondary air injection system.
Symptoms of a Bad Air Pump Control Valve
The air pump control valve can malfunction for reasons like electrical issues in the solenoid control circuit and compromised seals in the valve itself that allow air to leak out or admit exhaust gases into the AIR system. Inspect your vehicle’s valve when you encounter any of these warning signs associated with a bad unit:
- Illuminated or blinking check engine light
- Dark and smoggy exhaust
- Failure to pass an emissions test
The PCM may also log an OBD-II diagnostic trouble code related to the secondary air injection system if it detects a bad or failing air pump check valve. Code P0411 (Secondary Air Injection System Incorrect Flow Detected) warns about the air flow in the system going the wrong way, which may mean the check valve got stuck in the open position.
How Much Does an Air Pump Control Valve Cost?
Factors like the parts manufacturer and the year, make, and model of the vehicle determine the price tag of a new air pump control valve. You can end up paying anywhere between $35 and $80 for a replacement part. These valves usually come in individual units or a set of 2 valves, the latter being for those who need or want a spare valve for a rainy day.
Choosing a New Air Pump Control Valve
You have many things to consider while browsing the many air pump control valve products on the market.
The most important factor is compatibility with your vehicle. You want the new valve to fit on your car and work just as well, or even better, than the old unit.
There’s no such thing as a universal part since car manufacturers stick to their design preferences. Thus, a BMW air pump control valve isn’t compatible with a Saab vehicle, and likewise a Saab air pump check valve will probably not fit on a BMW.
Our website can help you find an air pump control valve guaranteed to fit your vehicle. By entering the year, make, and model of your car in the site’s filter bar, you can quickly go through our wide selection of top quality air pump check valves.