VW 2.5 Secondary Air Injection Incorrect Flow (P0411)

December 8, 2015

The secondary air injection system’s job on your VW 2.5 engine is to prevent excessive emissions.  A bad component in this system is almost sure to set off a check engine light.  Generally the fault code would be something like “P0411 – Secondary Air Injection Incorrect Flow”.  The important thing to note is that when you have this fault code it points you in the direction of the secondary air system, but you will still need to track down which component is causing your issue.


What does the Secondary Air Injection System Do?

The Secondary air system’s basic function is to use an air pump (for VW generally electric) to force additional air into the exhaust on cold start.  Pumping the air into the exhaust has 2 main functions, both of which are emissions related.  1 Pumping additional oxygen into the exhaust helps break down hydrocarbons (essentially unburned fuel), this is required as vehicles run richer on cold starts.  2 Pumping that air into the exhaust will heat the catalytic converter up quicker allowing it to reach its efficiency range quicker.



Sounds Fancy but Why Do I care?

If you have an issue with your secondary air system your VW 2.5L engine will set a check engine light.  Check engine lights in pretty much all parts of the US means you will not be able to pass inspection.  So you need to address this issue to pass.  You also need to fix this to prevent further damage to parts in this system.  Take a look below for a little more on that.


VW 2.5 Secondary Air Component Location


What parts do I need to replace?

This system is pretty simple on the VW 2.5 engine, it consists of an Electric Secondary Air Pump, Electric Combination Valve, and the hoses and pipes that connect them.  You will need to track down which of these is your issue.  There are generally only a few ways these fail

  1.  The Combination (N112) Valve Stops Working (may be stuck open or shut)
  2. The Secondary Air Pump Stops Working
  3. There is a leak in one of the hoses bleeding off the air the pump is making
  4. The Secondary Air Pressure Sensor (failed sensor not reading)
  5. Bad Mass Air Flow Sensor (Less Common)
  6. Bad Oxygen Sensor (Less Common)

Its important to note that if your combination valve get stuck open you will need to repair this as soon as possible.  A stuck combination valve will force condensation from the exhaust into the secondary air pump.  This will generally cause the pump to fill with water and eventually will destroy the pump as well.


VW 2.5L 5 Cylinder Combination Valve 07K131351C

VW 2.5 5cylinder Combination Valve


VW 2.5L 5 Cylinder Secondary Air Injection Pump 07K131333A

VW 2.5 5cylinder Secondary Air Pump


Secondary Air Injection Pipes


If you have a 2006-2008 VW 2.5 Engine up to production date 6/30/08 you would need to swap to a replacement kit that includes a new updated pipe, pressure sensor and connector adapter.

2.5L Secondary Air Pipe Kit with Sensor and Adapter 07K198125

Paul Barrett


CEO | Ex Dealer Technician | VW Audi Parts Savant | Father | Husband | Chipotle Enthusiast
Creating a VW and Audi Parts Company that Cares


on VW 2.5 Secondary Air Injection Incorrect Flow (P0411).
  1. Alina Postepski

    Thank you for an excellent info and description of the system.
    It will make me less anxious going to the repair shop and understand
    invoices. Alina

    • Paul Barrett

      Awesome glad we could help…. We can also help save you money on repair parts too ; )

  2. Alexandre Alfieri

    Hello friend, for JETTA 2.5L 2010 will need to change the kit 07k198125 ?? My car had the P2433 error, then changed the MAP sensor and then changed the error to P2431 . Can it be a problem in combination valve ? Thank you.

    • Paul Barrett

      You will have to look into this further its possible the you might have issues with the pump combination valve or other components. A proper diagnostic is needed.

  3. Viridiana

    My 2001 Volkswagen Beetlehe check engine turned on so I had it scanned and the code p0411 popped up. What do I need to fix or replace?

  4. Dave Blankenship

    What is the proper method to test the combination valve? The Bently manual says to supply vacuum to the port, but it’s electric not vacuum.

      • Dave Blankenship

        Is there an alternate method? That’s an expensive tool for something that will almost never get used. The pipes all look good & the motor runs for about 30 seconds on a cold start. The car belongs to a high school kid that can’t afford to just throw parts @ it & hope something sticks.

  5. Rob

    My Eurovan is a 94 model 2.5L gas and I found a melted secondary check valve (part no 037-131-367) and a melted pcv valve as they are both right next to each other. I tracked down a pcv valve without an issue but the check valve was almost impossible to find except for 2 which I ended up paying top dollar for and just received it but before installing it I just wanted to get a a professional’s response. Just to confirm that the direction of the arrow on the check valve would be toward the kombi valve that it plugs almost directly into and that it would most likely of been the pcv valve that would of melted the check valve as the check valve only blows air and not soot? Or is their any way the check valve could of been the reason as to why they melted or a malfunctioning kombi valve?

  6. |

    What, specifically, is the reason a 2006-2008 2.5L Engine needs to swap to the replacement kit 07K198125.

    • Paul Barrett

      Everything on the vehicles was changed. So you need to replace all the parts as the old versions are no longer available.

  7. My Jetta engine was on then went out when I filled the tank why?

    My VW Jetta engine light was on yellow light then went off when I fill the tank.why ?

  8. |

    Our secondary pump runs perfectly when connected to the battery directly. However, it will not run when connected to the wire harness. The wire harness has negative voltage but no positive voltage. Could you explain what controls the actuation of the positive voltage.

  9. Feliz Rodriguez

    I am not having any luck with my diagnosis. The pump works when bench tested, but it will not turn on the car. I need the location of the fuse and relay that goes to the pump since I think that to be the issue. Kombi valve works, solenoid seems to work and I checked every hose for leaks. In Vag-Com I tried to run a test and it will not go on test mode.

  10. |

    I have a 2008 jetta 5cyl i dont have a check engine light on but it didnt pass the smog is the same prosses test for this too

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