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I own a 2009 Audi S5, with the 4.2L V8 FSI engine. This also applies to a 2008 Audi S5.
I encountered the following errors and managed to fix it. I'll give it my best shot to explain everything that I learned, although I am no expert. Use this information at your own peril.

P2004 = Intake Manifold Runner Stuck Open Control Bank 1
P2005 = Intake Manifold Runner Stuck Open Control Bank 2

P2006 = Intake Manifold Runner Stuck Closed Control Bank 1
P2007 = Intake Manifold Runner Stuck Closed Control Bank 2

I believe you get the first two or the second two, depending on the position that the runner is stuck in. Closed is more common.

I have the magnesium intake manifold (change over to plastic was midway through MY2009). If this is what you have (manifold is metal), then this would apply. If you have the plastic manifold, I'm told that is actuated by vacuum tubes, so this mostly will not apply.

There are a set of flaps directly upstream of the intake valves. Their function is to change the effective diameter of the intake runner at different RPM to improve power and efficiency. They come in a pair since it's a V8, running along both sides of the intake manifold, four flaps on each shaft, two shafts. The shafts comes out of the front side of the manifold. A motor (lower drive unit) connected to two linkages actuates the shafts, and a sensor on each shaft (Bank 1&2) checks if they made it to the correct position. If the sensor reports that the flaps are not in the correct position, the engine concludes that the flaps are stuck closed, or open.
(Note that this is not related to the variable intake flaps in the center of the manifold, which is actuated by the upper drive unit. This is concerned with the lower drive unit)

In some cases this is because of a known problem with the actuator motor. Part 079129086 was replaced by 079129086B. The original motor did not rotate far enough. In which case you'll need to replace the motor with the "B" part.

If you're getting *both* codes of either P2004&P2005 or P2006&P2007, chances are that the position sensors are fine, and the flaps are not making it into position. This can be because:
1) Resistance in the flaps. Carbon build up can get in the way of the flaps, or into the bearings. The flaps may warp. It is easy for there to be an alignment issue in the manifold. You may be able to carefully remove the E-clips and pin that attach the drive unit linkage to the lever on the shaft, and see if the flaps can be moved on their own while disconnected. Do not try to force the drive unit to rotate! It does not move, and if it does move, it is likely broken.
2) Linkage broken. The linkage should be firmly attached to the drive unit, and should not move (do not force it).
3) Drive unit electrical connection issue. There could be a problem with the connector or wire to the actuator motor. Although that may trigger another code, I'm not sure.
4) Drive unit internal issue, e.g. burned out. I'm not sure how you would troubleshoot an internal issue in the motor, besides replacing.

Note that case #2 and case #4 might have happened as a RESULT of case #1 (flap resistance/stuck), so check the flaps when disconnected from the drive unit.

In case #1, #2,#4, you'll have to remove the intake manifold. There are very detailed instructions for removing the intake manifold in the service manual. I got mine at alldatadiy.com .

In case #1, you'll have to find out what is resisting the flaps. This could be carbon on the flaps, shaft warping, carbon in the bearings, etc.. At best, you can clean it up. At worst you'll need to replace the whole manifold ($1600). The manifold cannot be disassembled, it is sealed and there is no way to take it apart without destroying it. The manifold is fundamentally a bad design, likely why it was replaced mid-MY2009.
If the drive unit needs replacing, the part is about $400, and can be swapped when the manifold is out. Again, this might only fix it temporarily if there is flap resistance.

One more note, if you’re getting only one individual fault code, and they are not coming in pairs, then it is probably one of the sensors that is your problem.

bglynn7374

This is an excellent write up. I am surprised to be the first comment. Though I have a 10 s5, it turns out my SUV VW Touareg 2008 has the same engine. I have recently begun to ping these codes in the VW. P2004, p2005. This is all related to the variable length intake runners and the control flaps. I have taken the linkages apart very carefully. Although I cannot see inside the manifold to see their true travel the potentiometer arms move freely through what range feels natural. When the engine is running and revved you can see the motor, linkages, and arms all move. My local VW dealer has no experience with this and simply wants to change the $1700 manifold assembly. You can purchase the drive motor and potentiometers separately, you mention the drive motor but potentiometers are 03C907386E. This thing is a real problem to sort out. So far there has been limited performance loss but I am sure the flaps are leaking if they do not close correctly. Anyone have any other advise?

Michael LaNasa

I have the same issue with my Audi S5. I took mine apart for carbon cleaning. Put it back together and got a p2006 code. There’s not any lose vacuum lines. When I start the car all of the control arms move. I took it back off, Bank 1 side the flap moves freely with touch. Bank 2 would move and was open. The code is for bank 1. Not sure what to try next.

yourDIYneeds

May this video helps .

Rick106

Ive got the same issue with a P2007 after a carbon clean. Did you find what the issue could be?

R8 Jedi

Hi
I have an Audi R8 2013 done 19k miles and have error code... P2004 = Intake Manifold Runner Stuck Open Control Bank 1.
I have two questions...
1. when standing behind the car (Right hand drive) is bank 1 the right or left one?
2. Because of the mileage i dont think its a carbon build up issue. what could it be, the Potentiometer? is this the same as Actuator?