Crosspost from AUDIZINE: Looking for someone who has experienced RS5 error codes 2004/2005. Here’s the story: I removed the rear intake tubes and shot a can of “intake valve cleaner” into the throttle bodies per instructions. Brand was STP. Wasn’t experiencing any obvious indication of carbon…just “why not”?! Immediately after, EPC light came on, codes checked and cleared but they come right back…2004/2005, Banks 1/2 Intake Manifold Flap stuck open. I had several thoughts about the cause and I’ve been working through them: 1) I dislodged enough carbon that the flaps stuck open. 2) I melted the flaps with the cleaner. 3) I knocked a vacuum hose or 4)some sensor wire loose doing the cleaner injection. Or 5) I somehow damaged the sensors with the cleaner.
So, I’ve confirmed the following…a) flaps move upon startup…I assume that is “closing them”. I also can move them with my finger reaching down under the vacuum motor actuator on the drivers side front. Engine vacuum is good. Good vacuum at the actuator; if I disconnect it the flap arm moves back, and the character of the idle shifts around, so I’m pretty sure they are actually moving. I feel like I’ve eliminated 1,2, 3…not sure yet on 4&5, but the actual sensors are way up front on the engine, so unless there is another connector or sensor back by the throttle bodies, I can’t see it being 4 either.
I’m not sure what to log to further diagnose. I tried logging Intake Manifold Runner Control but it just flatlined…car runs great, no other error codes, doesn’t seem to be down on power either at mid throttle or full bore. I’m NOT getting other error codes like Intake flap implausible signal, etc. that would suggest an electronic failure. Wonder if I should fog the intake with some more cleaner, but perhaps less aggressive, like Mass Air Flow sensor cleaner (yeah, I know we don’t have a MAF.)
Manual says I have to remove UIM to replace the sensors…I just used up my “wife grace” and “old man” soreness installing Michel’s tranny cooler (shoutout to Michel for that’s awesome kit!) so I’m trying to avoid removing UIM right now, but…
Thoughts?