P0411
Fix within 1-2 weeksThe Secondary Air Injection System is not flowing the correct amount of air into the exhaust.
Code P0411 means the secondary air injection system has incorrect air flow. Common causes: Air pump failure (50%), check valve failure (30%), hose leaks (15%). Drivability: Yes, safe to drive. Repair cost: $50-$500 DIY, $200-$800 professional.
Can I Drive With P0411?
Yes, safe to drive
No restrictions
Stop driving immediately if: No need to stop driving unless other symptoms like significant power loss or loud noises develop (which are not typical for P0411).
Symptoms of P0411
- 1Check Engine Light is on
- 2No noticeable symptoms (most common)
- 3Slight whistling or whirring noise from the engine bay on cold start
- 4Rough idle on cold start (less common)
Common Causes of P0411
Parts most likely causing this code, ranked by probability
The electric pump responsible for pushing air into the exhaust fails, either electrically or mechanically, preventing proper air flow.
50% of P0411 cases are fixed by replacing this part
One or more check valves stick open or closed, preventing fresh air from reaching the exhaust or allowing exhaust gases to damage the pump.
30% of P0411 cases are fixed by replacing these parts
Cracks, leaks, or blockages in the air delivery hoses or pipes prevent the secondary air system from functioning correctly.
15% of P0411 cases are fixed by repairing these components
A faulty relay or blown fuse prevents power from reaching the secondary air pump, stopping its operation.
5% of P0411 cases are fixed by replacing this part
Check These First (Before Buying Parts)
- Listen for the secondary air pump on a cold start.
- Check the secondary air pump fuse and relay.
- Visually inspect all secondary air system hoses for cracks or disconnections.
How to Diagnose P0411
- 1Listen for the secondary air pump to activate on a cold engine start (it runs for about 30-90 seconds).
- 2Check the fuse and relay for the secondary air injection pump in your vehicle's fuse box.
- 3Visually inspect all hoses and pipes connected to the secondary air pump and check valves for cracks, leaks, or disconnections.
- 4Test the secondary air pump directly by applying 12V power and ground to ensure it spins.
- 5Test the check valves for proper one-way flow using a vacuum pump or by attempting to blow through them in both directions.
P0411 on Popular Vehicles
Toyota Camry
2007-2024Toyota and Lexus vehicles are prone to secondary air pump and check valve failures due to exhaust gas corrosion or motor wear. Often, both the pump and check valves need replacement.
75% fixed by replacing pump and/or check valves
Honda Accord
2003-2024Honda Accord models can experience P0411 due to secondary air pump motor failure or issues with the air switching valves. Inspecting the vacuum lines to the valves is also important.
70% fixed by replacing pump and/or check valves
Ford F-150
2004-2024Ford F-150 trucks often see P0411 from a failed secondary air injection pump, especially in areas with high moisture or road salt. Check for corrosion on electrical connections.
60% fixed by replacing pump
Frequently Asked Questions
What does P0411 mean?
P0411 indicates that your vehicle's computer has detected an incorrect flow of air in the secondary air injection system, which is designed to reduce emissions during cold starts.
Can I drive with P0411?
Yes, you can drive safely with a P0411 code. This code typically does not cause immediate drivability issues or put you at risk of breaking down. However, it is an emissions system fault and should be addressed within 1-2 weeks.
Will P0411 clear itself?
No, P0411 will not clear itself. The Check Engine Light will remain on until the underlying issue with the secondary air injection system is diagnosed and repaired. Once fixed, the code can be cleared with an OBD-II scanner.
How do I fix P0411 myself?
To fix P0411 yourself, start by checking the secondary air pump fuse and relay. Then, visually inspect all hoses for cracks or disconnections. If those are good, you will likely need to test or replace the secondary air injection pump or the check valves.
How much does it cost to fix P0411?
DIY repair costs for P0411 range from $50 for a relay or hose to $500 for a new secondary air pump and check valves. Professional repair costs typically range from $200 to $800, including parts and labor.
P0411 keeps coming back - why?
P0411 keeps coming back because the root cause was not fully addressed. This often happens if only one component (like the pump) was replaced, but a faulty check valve or a hidden hose leak was overlooked. Thorough diagnosis of all system components is critical.
Will P0411 fail emissions/smog test?
Yes, a P0411 code will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on for any emissions-related fault is an automatic failure in most jurisdictions.
What's the difference between P0411 and P0410?
P0410 indicates a general 'Secondary Air Injection System Malfunction,' meaning the system isn't working at all. P0411 is more specific, indicating 'Incorrect Flow Detected,' meaning the system might be running, but the computer isn't seeing the expected air volume or pressure.
P0411 on Toyota Camry
On many Toyota Camry models, P0411 is frequently caused by a failing secondary air injection pump or stuck check valves. These components are known wear items and often require replacement after 100,000 miles.
Questions to Ask Your Mechanic
Did you check the secondary air pump's operation on a cold start?
Good answer: Yes, I confirmed the pump is either not running or running but not producing adequate pressure. I also checked its fuse and relay.
What did you find when testing the secondary air injection check valves?
Good answer: I found that one or both check valves were stuck open, allowing exhaust gases to backflow, or stuck closed, preventing fresh air from entering the exhaust.
Repair Cost Estimate
DIY Repair
Parts only
$50-$500
Shop Repair
Parts + labor
$200-$800
Save $150-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires some electrical testing and component access, but is manageable for a DIYer with basic tools and a multimeter.
Cost of Waiting
Ignoring P0411 means your vehicle is producing higher emissions during cold starts. While it won't immediately damage major components like a misfire, it will cause you to fail emissions tests and contributes to air pollution.
While You're In There...
These valves often fail around the same time as the pump or can cause pump failure. Replacing them together saves labor.
Hoses can become brittle and crack over time. Replacing them while the system is apart prevents future leaks and repeat work.
Tools You'll Need
- Basic hand tools (sockets, wrenches)
- Multimeter
- OBD-II scanner
- Vacuum pump/tester (for check valves)
P0411 is a common emissions code. Most repairs involve replacing a specific component like the air pump or check valves, and your vehicle will pass emissions afterward.
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Your Next Steps
Step 1: On a cold engine, listen for the secondary air pump to run for about 30-90 seconds after startup. If it doesn't run, check its fuse and relay.
Step 2: If the pump runs or the fuse/relay are good, visually inspect all hoses and pipes for cracks, leaks, or disconnections. Repair any damage found.
Step 3: If the above steps don't fix it, you will likely need to test the secondary air pump and the check valves. Parts you'll likely need include a new secondary air injection pump or one or more secondary air injection check valves.