Complex emissions components minimize the pollution of vehicles in the environment while still meeting strict regulations.
One largely unknown system is the secondary air injection pump, which pumps extra air into the exhaust system after the vehicle begins, to further neutralize the exhaust. These pumps, however, will eventually fail with age.
There are a variety of symptoms that indicate a problem, which may be simple or severe. We will identify the symptoms to observe when emissions helpers need help themselves, and the costs to replace a secondary air injection pump.
What Is a Secondary Air Injection Pump?
Today’s vehicles have a secondary air injection pump, which pumps air into exhaust streams to offset the rich condition created at vehicle start-up.
This pump operates for about 30-120 seconds after start-up, under electrical demand from an ECM/PCM.
Additional airflow is used to more completely neutralize noxious emissions, especially in a rich operating condition.
The new air helps convert CO to CO2 and hydrocarbons to condensation water, and significantly reduces a vehicle’s carbon footprint.
O2 sensors monitor the operation of the secondary air pump. The engagement of the vehicle’s secondary air injection pump is seen by the O2 sensors as a lean condition and is sent to the vehicle’s ECM/PCM.
If the O2 sensors do not see a response to the secondary air injection pump, it is usually flagged as a fault condition, and the check engine light is illuminated.
Also in the secondary air injection pump circuit is an air solenoid, relay, check valve and a variety of vacuum lines. Failure of any of these essential components can cause complete or partial system failure.
Other Components of a Secondary Air Injection System
In addition to the pump, there are additional components of the secondary air injection system that help lower vehicle emissions.
The control relay, pneumatic control valve, a combination valve, and the engine control unit (ECU) are part of the secondary air injection system. Together, these components work together to ensure the pump can turn on with the correct amount of air and air flow in the secondary air injection system is properly operated in completing the secondary combustion process.
Also, the pneumatic control valve and the combination valve, allows exhaust gas to exhaust appropriately to keep the air pump from reaching exhaust gas to function properly and not be damaged.
The ECU, as the brain of the vehicle, coordinates all the systems to include all the pumps and valves, and establishes the correct time and conditions for the air.
Location of the Secondary Injection Pump
Typically, a secondary air injection pump is important at the front of the engine, as it draws air from the ambient air and supplies it around the serpentine belt; however, there are some vehicles where the pump may not be easily accessed, such as behind a plastic liner between the front wheel.
Either way, the mounting must leave enough clear area to easily pull in air and direct it into the exhaust stream to assist with emissions reduction.
Bad Secondary Air Pump Symptoms
A failing secondary air injection pump is always in conjunction with not only other symptoms; however, the severity of those symptoms seems to vary widely.
Those who recognize these symptoms might be able to easily diagnose the problem, thereby restoring the vehicle to its intended operating condition in quick order.
Below are the most common symptoms associated with secondary air injection pump failure:
#1. Check Engine Light.
One of the easiest symptoms you will be aware of when your secondary air injection pump is faulty is the ample warning of your vehicle’s check engine light.
A check engine light will illuminate when your vehicle’s ECM/PCM does not recognize a lean condition during the engagement of the secondary air injection pump. The most typical reason will be that one or several of the active diagnostic trouble codes were stored, such as P0410, P0411, P0412, P2440, or P2442.
#2. Erratic Idle.
In many cases, the absence of a secondary air injection pump activation will cause a vehicle engine idle to be set erratically, and in some cases, the idle will actually be lowered to a lower RPM or cause the engine to stutter, and sometimes stall completely.
This is as a result of the obvious effects that a secondary air injection lack of or lack of affects O2 sensor feedback.
#3. Reduced Performance.
Also, the reduction of a vehicle’s overall performance with a failed secondary air injection pump is completely evident. If accelerated, the reduction of performance in the majority of smogged vehicles will be a definite lack of power when it is time to accelerate.
If the severity of these symptoms becomes worse and worse, or not….
#4. Failed Emissions Test.
The failure of a secondary air injection pump on a vehicle will probably also be made evident in this case during the state-mandated emissions test.
The reason is that a vehicle’s exhaust output needs to be detected as running in a potentially much richer environment as the engine starts up, with no properly functioning secondary air injection circuit to assist combustion.
What Can Cause the Pump to Fail?
There are several issues that can cause an air injection pump to fail, creating a plethora of ramifications as a result. Some of the most common issues that can develop upon a pump’s failure are as follows.
#1. Inadequate Power/Ground Delivery.
High resistance of a secondary air injection pump’s power or ground circuits can be detrimental.
A pump with an inadequate power or ground supply is forced to work harder, creating extra heat, as it improperly draws power.
#2. Faulty Vacuum System.
Vacuum system leaks and blockages will cause a secondary air injection pump to operate inefficiently. Both of these conditions will lead to a pump working too hard, and experiencing wear and tear prematurely.
#3. Contamination by Water.
Over time, water can gradually enter a vehicle’s exhaust system, eventually working its way to several locations where it does not belong. One of these locations could eventually be a secondary air injection pump housing.
The leading cause of corrosion that substantially reduces the service life of many of today’s secondary air injection pumps is indeed water contamination.
#4. Age.
In some cases, a secondary air injection pump simply fails because it has reached the end of its useful life cycle. As with any mechanical part, secondary air injection parts are not exempt from normal wear and tear, and aging pumps of this type do occasionally fail.
Can You Drive Without a Secondary Air Pump?
You can technically drive without a secondary injection pump. However, that isn’t recommended.
This is because a defective secondary injection pump cab creates a variety of drivability related issues that can be quite variable and depend heavily on the condition.
For example, a secondary injection pump that does not operate can cause your vehicle’s engine to respond erratically to throttle input, especially under load.
One can expect a certain level of backfiring, and that is to be expected, anytime a person operates a vehicle with a faulty and otherwise inoperable secondary air injection pump.
Motorists might also find it impossible to license their vehicle in states or counties with emissions testing, when trying to operate with a secondary air injection pump that is faulty.
This condition can lead to an engine that runs rich excessive at start up.
Secondary Air Injection Pump Replacement Cost
As with any repair, the price related to secondary air injection replacement is highly variable between vehicle models.
This is perfectly understandable, as there are so many variables, including the amount of labor time to complete a repair, and the price of the replacement air pump.
Nonetheless, the average cost to replace the secondary air injection pump is generally within a range. In other words, the price for a replacement or new secondary air injection pump will generally fall between the range of $250-$450 of perhaps $325 being a relative average.
Once again, the final cost to complete any repair will ultimately depend on the complexities of the repair, who is doing the work, and the price of the needed replacement parts..