Hi I'm new to the forum and VW/Audi’s and I hope I can find some information/help from other members. I will keep this post updated until the issue is resolved and can share with the community. I have done multiple searches and haven't found anyone with the vacuum actuated flaps, with my specific problem.
There are several posts regarding early 2009 and previous models with the intake manifold flap motor/linkage, however I have the plastic manifold with the vacuum actuated flaps. Generally these issues stem from a defective vacuum solenoid or a vacuum leak but both seem fine to me. Also, the vacuum actuators hold vacuum when testing with a vacuum pump and gauge. The position transducers read linearly when operating them as well. Everything seems to work mechanically. As far as it operating electrically, I do not know exactly when the ECU commands the vacuum solenoid to activate but when it pulls the solenoid to ground, both flaps physically actuate. Definitely when less than 60 degrees C, the solenoid is energized and the actuators open to 99%. When operating at normal running temperature, they close to 0% and then seem to open based on a combination of RPM, throttle angle and engine load. I’m not sure as the logs I have from VCDS don’t exactly correlate to what I physically see when comparing set position to actual position.
Codes P2004/P2005 (stuck open) appear when the solenoid is activated and the flap position is high (>80%) and P2006/2007 (stuck closed) appear when de-energized and the flap position is low (<10%).
I do have VCDS and have used it to troubleshoot this issue. Using the output test function, the vacuum actuators move from 3.5% to 99.6% (Bank 1) and 10% to 99.6% (Bank 2). There are no vacuum leaks on the circuit. However when the set position is 0% and the solenoid is pulled to ground (activated), the actuators move to 99.6% and I receive P2006/2007 (stuck closed). Likewise when the set position is 99.6%, the solenoid is de-energized and the actuators position is 3.5% and 10% I receive P2004/2005 (stuck open). In my opinion this doesn’t make sense for the feedback to be opposite of the set point but have not ever monitored this when it was working normally. I also get an adaptation error for both banks and have not been able to successfully re-adapt the manifold flaps. This is what I believe causes the errors but I’m not sure as I can’t see this all of a sudden inverting.
Can anyone else with an S5, with vacuum actuated flaps do me a favour and verify if the set vs. actual position is inverse or proportional, using VCDS for me?
I was able to trick the ECU into adapting the flaps using VCDS and manually controlling the solenoid (with homemade jumpers directly on the solenoid). Now my flap positions are 0% to 85% but the adaptation error re-appeared after starting the car again. It appears like the actuators don’t seem to go the full range (0-99.6%) possibly due to carbon build up, but now that the position can read 0% closed, I still get the stuck closed error or even stuck open when at 85%. Also, what throws me off is that both banks errors occurred at the exact same time and have never got a MIL for just one of them. Therefore I find it hard to believe it is due to carbon build up as they are independent and don’t want to pull the intake manifold if I don’t have to.
Sorry for the long post and appreciate you taking the time to read it. This is my first VW/Audi but I am technically inclined and hope someone with more knowledge and experience with these vehicles can assist. I do have a few data logs that I can share with anyone willing to analyze and help me out. Any suggestions/help is appreciated. Thanks in advance.
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