The air injection pump in the Toyota Tundra is also known as the secondary air injection system. It is the part of the exhaust system that helps reduce hydrocarbons and carbon monoxide emissions in the air. It is standard in Toyota Tundra models that were launched in the years 2000, 2001, 2005, 200,6,2007, 2008, 2009, 2010, 2011, 2012, and 2013.
Toyota Tundra air injection pump problems include air injection pump failure, uneven sound, clogged and blocked system, electric issues, leaking lines, sensor failure, valve rusting, and limp mode activation.
My friend had the 2013 Tundra a few years back and experienced the same issue. He told me about the decreased fuel economy because of air injection system failure. The fuel economy in his truck decreased because of the high ratio of unburned fuel.
In addition, he also faced the problem of increased emissions from the exhaust system. He spent almost $600 on replacing the air injection pump, including the labor cost.
| Problems | Solutions |
| Air injection pump failure | Replace pump |
| Uneven sound | Check MAF sensor mounting |
| Clogged and blocked system | Keep airlines clean |
| Electric issue | Check ground connections, fuses, and relays |
| Leaking lines | Reduce the risk of engine overheating |
| Sensor failure | Clean sensors with MAF cleaners |
| Valve rusting | Use carbon-dissolving cleaners |
Air injection pump failure
The air injection pump’s main function is to supply the oxygen-rich air into the exhaust manifold for air and fuel mixture ignition. A failed pump is not capable of supplying the air to the combustion chamber, which increases the emissions of harmful gasses because of fuel unburned fuel.
Unburned fuel comes out from the exhaust system and increases the risk of environmental pollution. Their parts are vulnerable to failure because of their age and extended use.
The mechanical components of air pumps wear out because of their age. In addition, they also stop functioning because of faulty ECM systems.
ECM system powers this electric pump to supply air to the exhaust system. It does not function because of the failure of the engine control module.
It can also fail because of insufficient power supply. It can get damaged because of water infiltration and a damaged vacuum system. I also experienced this problem in my Toyota Tundra while towing my small camper.
I saw the check engine light on the cluster screen and inspected the engine parts. My truck’s engine was not overheating, but I also checked the air injection system because of high emissions.
The pump was badly corroded because of water exposure. I replaced it with a new one because corrosion on its parts is irreversible. It is necessary to replace the failed pump because you cannot pass the emission test to comply with safety rules and regulations on the road.
Increased emissions from your vehicle do not allow you to pass the test. These are located in the engine compartment, and you have to remove the serpentine belt to access their parts.
Detach the clips that hold these parts and remove the vacuum lines and hoses. Install new pumps and ensure their correct electric connections for their smooth functioning.
Uneven sound
Many people complain that they hear the knocking sound from their trucks on cold start. Low-frequency knocking and popping sounds indicate that something is hitting the metal components because of incorrect installation or loose attachments.
The issue can also come because of the incorrect installation of a mass airflow sensor that regulates the amount of air entering the exhaust system.
In addition, you can also hear the loud popping sound on cold start. The issue also comes when mass air flow sensors become loose. Loose sensors cause the metal parts to hit the brackets and produce loud noise while starting your vehicle.
You can hear it for 10 to 20 seconds when starting your Tundra truck. Check the mass air flow sensor and its mounts to stop the noise coming from the engine compartment. Tighten the sensor mounts to decrease their bracket hitting with a metal material.
Clogged and blocked system
Clogging and blocking the air injection system is common, which impedes the smooth airflow to the combustion chamber. It also affects the overall performance of your truck by blocking the airlines.
Because of clogged airlines, you can face issues of rough idling and hard acceleration in winter. Air lines of injection systems can clog because of carbon buildup.
Carbon is the byproduct of the combustion chamber and accumulates in the exhaust system. Moreover, the issue also comes because of condensation, which leads to moisture exposure.
Moisture combines with other materials and forms a thick sludge, which affects the smooth airflow between the lines. In addition, airlines can also block because of clogged filters, poor cleaning, use of fuel additives, and temperature changes.
You can decrease the clogging issue by using specialized tools for airline cleaning. You should keep them clean and inspect them twice a year to reduce the risk of any serious issues while driving. However, clogged lines also cause decreased power supply, which leads to limp mode activation in your Toyota Tundra.
Electric issue
The secondary air injection system in your vehicle is the electronically controlled components. It is connected with electric wires that take power from the Toyota Tundra batteries.
In addition, these also have fuses and relays for their smooth functioning. Fuses are helpful to reduce the risk of damage to their components.
They fail to perform their function because of electrical issues. These cannot work because of dead and weak batteries of faulty engine control modules of your vehicle.
One of my neighbors also faced a faulty air injection system issue in his truck because of weak batteries. He checked the batteries, and they did not have sufficient charge.
He told me he did not replace his truck’s battery for 5 years. He replaced the battery, restarted his vehicle, and went for a test drive to ensure the correct functioning of the engine and exhaust system.
Moreover, you can also face issues because of faulty and poor ground connections. It is better to check ground connections and ensure these are not loose and corroded.
Leaking lines
You can see a hose leaking issue in the secondary air injection system. These contain rubber hoses through which air travels to the combustion chamber to burn unburned fuel.
These rubber hoses are vulnerable to cracking and breaking because of their age and delicate material. In addition, they become brittle because of high engine temperature.
The brittle rubber material can crack easily and cause air leakages. Oxygen-rich air cannot move to the combustion chamber, which results in a reduced power supply.
Moreover, you can also see a fluctuating power supply. You should avoid driving your Tundra when the engine overheats because high temperature affects the working efficiency of nearby components. It causes hardening and cracking of rubber material.
Sensor failure
Air injection systems contain mass air flow sensors that monitor the air supply to the exhaust system. Sometimes, these sensors become faulty and affect the functioning of an electric pump.
These sensors have specific life, and you have to replace them after the recommended miles. In addition, dust and debris can come on these sensors with air, which increases the risk of their failure.
These cannot function because of their loose mounting. Moreover, water ingress and oil mist from the crankshaft ventilation affect their chances of damage.
It is better to clean it properly to reduce clogging chances and enhance its working efficiency. Detach the sensor from your truck and use MAF cleaner to remove dust and debris.
Valve rusting
The air injection pump stops functioning and cannot supply sufficient air for the ignition. The issue comes because of the rusting of their components.
These are vulnerable to rusting because of water ingress. You can face the issue because of driving your Toyota Tundra over the water puddles. Water can also come into them through the air duct of the engine.
Tailgate pipe condensation is expected, which causes the steam to corrode the metal parts of the air injection system. You can remove the corrosion and decrease the risk of the pump seizing by spraying the carbon-dissolving cleaner on the affected surfaces.
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