[330istocknot]

Hi All,

Recently i had 6 codes on my DME, and slowly replaced the following:

-Alternator
2 X Vanos Solenoids
-Broke radiator hose when putting back air filter, so i replaced the hose from radiator to engine.
-Tensioner pulley

and got rid of all 5, but there is still 1 more code left...

Long story short, my car still struggles on low RPM, 1-3K RPM, when AC is on, there is hesitation. I purchase a BMW code reader, and i am getting 2AAC.

2AAC - Variable Intake System 2 - Self Diagnosed.

I noticed that the car has 2 DISA Valve, is this code indicating replacement of either one? How to check if these DISA are bad.

I have family coming over this week and would love to take them around with my vehicle, that im always bragging about... I've worked all last week to replace all issues to have it running by the time family come over, now im left with this 2AAC... Any ideas where to start?

[The Nightman]

The servo motor in the small DISA valve is faulty. I'm dealing with the same problem and replacement is the only solution that I'm aware of. Unfortunately the small DISA valve is on the "inside" of the intake manifold and will require removal to access

[330istocknot]

Originally Posted by freedomfries

The servo motor in the small DISA valve is faulty. I'm dealing with the same problem and replacement is the only solution that I'm aware of. Unfortunately the small DISA valve is on the "inside" of the intake manifold and will require removal to access

Are you getting the same DME code? How difficult is it to replace that? Also how do we know is not the one outside by the driver side?

[330istocknot]

bump?

[330istocknot]

Even though not many responded i will update my finding for future references, and may help someone else next year or 10 years from now.


The code 2AAC means one of both DISA is bad, the one outside on the drive side, and the one inside under the manifold.

Here i checked the one outside by the driver side. It looks like the DISA is stuck in the open position. This seems to be my problem. I will buy and replace this part tomorrow. I will update if it solved the issue.

[The Nightman]

The DISA valves are supposed to be in the open position with no play when unplugged.

You can test the valves using INPA. Check out the DISA threads in the non-turbo subforum

[330istocknot]

Originally Posted by freedomfries

The DISA valves are supposed to be in the open position with no play when unplugged.

You can test the valves using INPA. Check out the DISA threads in the non-turbo subforum

As soon as you turn the car on it should close right? You can hear the motor struggling to turn the flap. From what ive seen on other videos, it look like you can manually flip the flap, mine seems to be stuck. Check the video here.

[330istocknot]

Originally Posted by freedomfries

The DISA valves are supposed to be in the open position with no play when unplugged.

You can test the valves using INPA. Check out the DISA threads in the non-turbo subforum

What do you think of the video, looks faulty?

[The Nightman]

Originally Posted by 330istocknot

What do you think of the video, looks faulty?

As far as I know the valves only close when the engine is on. Everything I've seen so far suggests that your large valve is fine but it's hard to say for sure without testing it with INPA.

2AAC is specific to the small DISA valve because "variable intake system 2" is the small DISA circuit. If you search around you'll find others with the same fault code and replacing the small DISA was the only fix.

[e90yyc]

I would suggest using INPA to cycle the DISA valves and watching how they behave. Do they open/close cleanly and smoothly, or struggle/make noise etc...

[330istocknot]

update: Inner disa was replaced, and now car runs great! No hesitation, no jumpy RPMs, car has power again. Freedom fries was correct. The problem was the small inner disa inside the manifold.

Mine was stuck half way open, causing the 2AAC code. After replacing, 200 miles later, car runs better and smoother than ever, also my MPG is at 20.1 when normally was at 17-18.

So if you have this code 2AAC, it is a sure thing to replace this part as it will be faulty. Just thought i'd update.