[fox1486]

Hello all. I just attempted to do the PE mod (on driver's side only) to a spare N54 exhaust system. After replacing the resonator in the drivers side muffler box with a straight pipe, I installed the N54 system on my N55 e92 xdrive.

The previous owner looked like they did the "golf tee" mod with the vacuum line. However, I would like the butterfly valve to work properly. Problem is, after reconnecting the vacuum line and making sure the sensor in the truck was connected, I still am getting no vacuum to close the butterfly valve.

Can anyone suggest a solution? Is there a particular fuse that controls that valve? I see two vacuum lines coming off the solenoid, one to the butterfly actuator but I can't see where the other one goes.

[fox1486]

Just plugged in the Cobb AP, but did not install. Hidden code came up, 2F6C, showing the exhaust flapper solenoid was disconnected.

Would it be possible I need to reset the codes, or unplug the battery in order to get the flapper to work again properly?

[fox1486]

Still having this issue. Any help is appreciated. Thank you.

[weehe126]

So you have confirmed you are not getting any vacuum to the muffler? Then work your way back in to the engine bay and make sure it is connected. It starts on the drivers side, goes behind the engine and connects to the valve cover above the turbo.

[shawnsep]

As said by others, begin by isolating and checking vacuum at various locations.

My problem turned out to be a broken diaphragm for the exhaust flap. When plugged in, I can hear a whistling noise which is air entering the system from the diaphragm.

In order to get it operational, I plan on purchasing new vaccum and replacing the broken unit only. The other alternative is to get a used left muffler section with a working flap but it's bound to fail at some point in the near future.

Some links that may help.
https://www.autoserviceprofessional....w-exhaust-flap

https://www.newtis.info/tisv2/a/en/e...upply/JaZmwoDM