Volkswagen Secondary Air System
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P0411 Volkswagen/Audi Fault Code: Diagnosis & Repair

Chandler Stark

Meet Trey

Trey is an automotive enthusiast and has a huge passion for Volkswagen and Audi vehicles of all kinds. His enthusiasm started with the MK5 GTI, and he has massively expanded his knowledge over the years. When Trey is not delivering high-quality and in-depth content, we can usually find him working in his garage on his modified Genesis coupe. Trey created VW Tuning several years ago, and he is the primary visionary behind the content.

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P0411 VW/Audi Engine Code: Secondary Air Injection System – Insufficient Flow Detected

When a P0411 fault code for your VW pops up on your OBD scanner, it leads you directly to the secondary air injection system because it will read “Secondary Air Injection System – Insufficient Flow Detected “ but can cause confusion pinpointing the exact issue. As the definition states, the ECM has detected nonoptimal flow in the secondary air injection system. Within this post, you will find information on how to diagnose and repair the engine code P0411. It has been said that this code is most common in the 2.5 engines. Also, you will not pass an emissions test if your vehicle is reading the P0411 code.

Applications this affects:

  • VW Jetta
  • VW Golf/GTI
  • VW Beetle
  • VW Eos
  • VW CC
  • VW Passat
  • VW Rabbit
  • Audi A4
  • Audi A3
  • Audi S4

What is the Secondary Air Injection (SAI) system and what does it do? Essentially, the secondary air injection system’s main purpose is to inject air into the exhaust to lower emissions. When the secondary air injection system pumps extra air into the exhaust on a cold start, it serves two functions: it breaks down unburned fuel and it heats the catalytic converter at a quicker rate to reach your engine’s optimal levels.

The secondary air injection system is made up of many components: secondary air pump, secondary pressure sensor, combination (Kombi) valve, a control relay, and numerous hoses/pipes connecting the components.

The tough thing about a P0411 code is, most of the time, no other symptoms will be present except for the Check Engine Light illuminating. What symptoms can you look for when you get a P0411 engine code?

P0411 VW Symptoms

  • Check Engine Light (CEL) Illuminating
  • Secondary air pump making a whishing sound
  • Engine backfiring
  • Slight engine hesitation

Causes of P0411 Fault Code for Volkswagen

  • Secondary air pump failure
  • J299 Relay burnout
  • Combination (Kombi) valve failure or carbon buildup
  • Secondary air pressure sensor failure
  • Secondary air hose leak or carbon buildup
  • Bad Mass Air Flow (MAF) Sensor – Rare

How to Diagnose a Volkswagen with a P0411 Engine Code

It is hard to diagnose exactly what is wrong with the secondary air system when you get a P0411 code, but we’ll give you steps to lead you in the right direction to repair your vehicle.

  1. Plug in an OBD Scanner to confirm that you have a P0411 code
  2. Visually inspect the J299 relay associated with the secondary air injection system in the ECM housing and make sure it isn’t blown
  3. Visually inspect the secondary air pump
  4. Visually inspect the hoses/pipes attached to the air pump
  5. Visually inspect the Combination valve
  6. Visually inspect the secondary air injection solenoid valve (N112)
  7. Visually inspect the secondary air pressure sensor

The location for all of the parts listed above are in similar places for different engines, but here is a few pictures to help:
2009 – 2017 CC | 2008 – 2010 Volkswagen Passat | MK6 Jetta | MK6 GTI
Volkswagen Secondary Air Injection System Jetta
MK7 GTI & MK7 Golf
Volkswagen Secondary Air Injection System GTI
Credit to

How to Repair a Volkswagen with a P0411 Engine Code

The three most common causes for a P0411 fault code are burnt-out J299 relay, leaking secondary air pump, or combination valve failure. Since they are so many Volkswagen engines that have secondary air injection systems, we are going to do the 2.5’s since this failure does happen to occur on these engines the most. If you need more information on what parts you need for your specific engine, leave a comment below and we’ll make sure to get back to you as soon as possible.

Replacing the J299 Relay for a Volkswagen

2.5L Secondary Air Injection System Relay Location:
Volkswagen Secondary Air Injection Pump Relay
2.5L Relay Replacement

Replacing the Secondary Air Injection Pump for a Volkswagen

One way to test if your air pump is the reason for the P0411 code is to cold-start your vehicle and listen to the air pump to see if it is running. It should be running for 90 seconds after a cold start to inject extra air into the exhaust. If it is not, first check the J299 relay and if it isn’t burnt, then you will want to replace the pump. Another way to test a faulty air pump is to listen to hear if air is leaking out of the pump itself. If either of these is occurring, you will want to replace the secondary air injection pump itself.

Order Here: VW 2.5L OEM Secondary Air Injection Pump Replacement
DIY Difficulty:
*The above video is for a vw 1.8t but should point you in the right direction on how to perform this DIY

Replacing the Combination (Kombi) Valve for a Volkswagen

If the combination valve is stuck on open, you will need to fix this or take it into a shop ASAP. If this goes on for too long, moisture will invade the secondary air pump and ruin that part as well.

DIY Difficulty: Difficult


To sum it up, a P0411 engine code for your Volkswagen is something that needs to be fixed ASAP if you are in an emission-sensitive state or province as it will not pass the emissions test. We did only do the 2.5 Volkswagen engine because there are so many other engines this problem can apply to, so if you need assistance in figuring out replacement parts, diagnosis, or location of parts in another engine, please drop a comment and we’ll make sure to help you out.

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  1. I have a 2015 passat 1.8 and this picture you have is the only thing with my engine on it. No videos nothing. I have no idea where the combination valve is. Also my code is P0491, still the sai. Could this code cause my car to run bad? Loss of power and delay when I hit gas type of things? There’s also a tapping noise that comes and goes. Sometimes it’s quiet and other times it’s not. That is the only code it’s showing.

    1. Michelle,

      We have a write-up on the P0491 code that may be of assistance to you. It is the most recent fault code guide on our home page.

      Let me know if this assists you,

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