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P0411 OBD-II Trouble Code: Secondary Air Injection System Incorrect Flow Detected

Check Engine Light

P0411 code definition

The P0411 DTC is a generic OBD-II code that points to a malfunction within the secondary air injection system.

What the P0411 code means

P0411 indicates that the ECU has detected the flow from the secondary air injection system to be out-of-specification. This causes the Check Engine Light to be set and displayed on the dashboard. The light will remain on until normal operation occurs or repairs are performed.

What causes the P0411 code?

  • Air injection pump has failed
  • Air control solenoids or air lines are faulty
  • Open or short in wiring harness for air injection system
  • Air injection system has excessive carbon buildup

What are the symptoms of the P0411 code?

Most of the time the only symptom that is noticed is the Check Engine Light with no other adverse symptoms present. With some vehicles, a slight engine hesitation upon acceleration may be noticed.

How does a mechanic diagnose the P0411 code?

  • A mechanic will begin by using a scan tool plugged into the vehicle's DLC port to check for any codes stored into the ECU. There may be history, present, or pending codes each with their own freeze frame data.

  • Codes will be written down and freeze frame data noted and then cleared.

  • The technician will take the vehicle for a road test to try to duplicate the symptoms.

  • Once this is done, a visual inspection will be performed of the air injection system specifically looking for damaged hoses, excess carbon, or broken components.

  • Finally, an advanced scan tool will be used to monitor air pump operation.

Common mistakes when diagnosing the P0411 code

The most common mistake is made when unneccessary components are replaced within the air injection system - usually when parts are just clogged but have not actually failed. In these cases, the parts most likely just need to be cleaned.

Mistakes can also be made when steps are not followed in the proper order or just skipped entirely. This can lead to a false diagnosis and a waste of time and money.

How serious is the P0411 code?

In many cases, the driver will not notice anything out of ordinary with P0411 with the exception of the Check Engine Light being present. P0411 is directly tied with an emissions control system. This code will cause OBD-II emissions to be failed in many situations until it is resolved.

What repairs can fix the P0411 code?

Additional comments for consideration regarding the P0411 code

The secondary air injection system is important for reducing emissions in vehicles. It operates by adding air to the exhaust system which aids in the burning of environment harming tailpipe emissions.

A professional level scan tool is needed to properly diagnose the secondary air injection system. These scan tools allow access to data that is live from the sensors and solenoids. Technicians use this information to test the air injection system and determine which part is not functioning as designed.

In cases where carbon buildup has clogged secondary air injection system components, these parts may be able to be cleaned and unclogged. Specialized carbon cleaners are used to remove the carbon particles carefully.

Need help with a P0411 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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