Airbox power flap, VCDS and main dealer problems.

[mutantfatcat]

The airbox flap does not work on my car. I've tested it with VCDS and the solenoid doesn't even activate. I have also visually checked the flap which is stuck open, the valve that operates the flap is also broken or has unclipped itself from the flap housing.

I took the car to a main dealer today to have it repaired under warranty.

I picked the car up unfixed with the following report on the invoice:

"Carried out checks to the flap in the air filter b
fault stored in the memory fault has only occured
once, cleared fault and tested all ok."

Now beforehand, I read any faults out using VCDS and there were none.

From what I've read on here, the flap has no sensor and therefore no fault can be registered and stored anyway.

Does anyone know if the use of VCDS will invalidate any warranty. Will I be able to demonstate non function of the flap to the dealer using VCDS?

I guess it makes sense to visit another dealer as this one shows a serious lack of model knowledge/damn right lies if I am correct about the inabillity to log a fault related to the flap. But I would appreciate any views or experience anyone has had regarding VCDS and main dealers.

Thanks.....Lee

[lengster1]

If you have perfomed the function test with vcds and its not working then i would go back to the dealer and ask them to perform the test in front of you,my bet is they dont even know how to do it.

[lengster1]

Out of interest did you check BOTH engine ecu

[neckarsulm]

There is a solenoid (n335) that converts electric signal to vacuum as determined by the ECU
This vacuum is then sent to the flap valve via a pipe.
This solenoid could be defective and could log a fault
The flap itself is simple a vacuum operated actuator with no electronics, if this is faulty no fault codes are stored however if it's physically broken then I don't think there's any debate!

[silverRS4]

Neither ECU knows if the flap is stuck or doesn't open/close properly. That is part of the problem. Given the sensitivity of the RS4 to inlet air temperature, a faulty flap can cause serious issues and no MIL's will ever occur. There is no sensor on the air box flap mechanism. The manifold tumble flaps, on the other hand, have sensors - one for each bank. If they do not move as commanded, there will be an implausible signal MIL or something similar.

Ask the crap dealer what fault was stored in memory. On second thought, don't. That will simply give them another avenue for lying. Insist on them doing a function test of the flap when you are present. VCDS can not possible affect the warranty as it is basically the same diagnostic tool that the dealer uses. Simply tell them "The air box flap function on this car is very important. It is obvious the solenoid is not functioning. Please fix it."

Good luck!

[mutantfatcat]

Out of interest did you check BOTH engine ecu

All modules were read showing no faults.

[mutantfatcat]

Thanks silverRS4, especially for your great writeup on flap function testing.
I've booked in at another dealer so hopefully all will go well. However, if it doesn't, I will request that they perform the test in my presence.

Thanks.....Lee

[ArthurPE]

If you have perfomed the function test with vcds and its not working then i would go back to the dealer and ask them to perform the test in front of you,my bet is they dont even know how to do it.

+1

have them show you...

[RS6chris!]

Just a quickie...

The round airbox flap?? Can you move it by hand?to check it is moving freely. Or does the car have to be moving etc etc??

Also if the car is stood still and you rev it to above 5500rpm will you be able to see it in operation?

[silverRS4]

Yes the round one. Will it open at 5000 rpm while the car is stationary? Don't know. Let us know how that works out. I don't recommend it. But even if you do, I won't call Audi UK to tell them someone is free-revving the crap out of their RS4. I don't know how much VCDS costs over there, but it is well worth it even if all its ever used for is to check the vacuum-controlled components on the car.

[aidanjaye]

Yes the round one. Will it open at 5000 rpm while the car is stationary? Don't know. Let us know how that works out. I don't recommend it. But even if you do, I won't call Audi UK to tell them someone is free-revving the crap out of their RS4. I don't know how much VCDS costs over there, but it is well worth it even if all its ever used for is to check the vacuum-controlled components on the car.

Why not rev to 5k when stationary??? Less load.

[silverRS4]

Correct, less load. That means low effective cylinder pressure. Normally, low-load-high-rpm scenarios just increase blow-by past the rings...the rings need a certain amount of cylinder pressure to seal properly. If the pressure is low enough, the rings will actually flutter up and down axially in their respective groove. That can damage the ring and lead to premature wear in the bore. A few moments may not hurt anything at all. There are also very stresses caused by the inertia of all the various components accelerating much faster than they do when there actually is a load on the engine. So if someone insists on checking the flap when stationary, at least they could bring the RPM's gently. I would bet that since the ECUs are fully aware that the vehicle speed is zero that the flap won't open anyway. I will let someone else try it with their RS4. I thought someone here already did but I can't remember who.

[BlingBling]

But even if you do, I won't call Audi UK to tell them someone is free-revving the crap out of their RS4.

[P_G]

I believe the flaps open because I have done this to 5000 rpm when I have my P2020 code and a gradual build up and decrease off the throttle did reset the EPC light once. But I have only donw it once. When I knew this happend I did the rest when rolling.

[RS6chris!]

Any one gonna try it then??????????


Lol.