This DIY explains how to replace the VANOS Solenoid, with failure commonly detected through the following codes.

2A82 Inlet-Vanos variable cam control test
2A87 Outlet-Vanos variable cam control test
3100 boost-pressure control, deactivation
...

So I can use MAF cleaner, Or strictly just compressed air? I read through all the pages and im a little confused.

I used MAF cleaner

Howd it work out for you..? im hoping to get this done tomorrow!

Worked great, just spray and yiu will see the liquid come out (oily in color) spray until the liquid runs dry....you will know what I mean when you do it!blet dry a hour and re-install.

nice! but the MAF cleaner seems to evaporate almost immediately?

thst is actually a good thing about it...just spray until runs clear and then it dries fast.

I just went through the DIY and decided to clean my solenoids before replacing them. The problem was that under WOT it would occasionally/usually give me the yellow dashboard light which was described in the manual as "engine malfunction with adverse effect on emissions". So i removed both solenoids, cleaned them, and put them back on, but this time i put the exhaust solenoid in the intake hole and vice versa to see if it made a difference. When i started the car, everything seemed to be fine at the beginning so i took it to a test drive and after about 2 minutes of occasionally flooring it, the yellow light came on again and stayed on. Now it's always on. Quite terrifying. Any ideas guys?
Oh and my car is an lci 325i.

Okay so now i switched them back to their original positions and the problem persists. Yellow light constantly on even when i've just started the car.

turn car off, disconnect battery for a hour or so and see if this fixes it...if not dealer it or replace both.

Disconnecting the battery didn't work. Still getting the EML light. Will probably take it to a dealer to check soon. But do you really think replacing the solenoids will work? I can't imagine how the existing solenoids might have come to be defective. Perhaps i cleaned them wrong. I dipped the tip of the solenoids in gasoline and wooshed them around a little bit, let it dry off and put them back on. I read that technique in another diy and seemed logical. Maybe i should try and clean them again with MAF cleaner? I wonder if there's anything else that could be faulty besides the solenoids?

gasoline??? Try MAF cleaner...spray until it runs clear.

Yeah, just finished trying that. Cleaned with crc maf cleaner extensively. Now i put the solenoids back on and the yellow light was on immediately after turning on the car. Not sure if the engine was acting any different though. I dare not take it for a drive to find out.

Do you have a tune you can get the codes it us throwing? Is your oil in you car full?

Unfortunately i don't have anything with which to read fault codes. The computer says the oil level is ok. It was last changed about 5000 kilometers ago.

Okay so i have some new information. I took it for a short test trive around the block, since the engine seemed normal while idling and everything was okay, the acceleration the sound, even at WOT at low rpm. Before i cleaned my solenoids it started to stutter at WOT like power/no power very rapidly. Now it seemes okay. Another interesting thing is that the yellow light comes on even when i just turn on the ignition and not the engine. All the lights come on, then all go off except for the yellow engine light.

Now i did another test drive and it's really weird again. Stutters constantly, especially at low rpm. Perhaps a cylinder misfire? Gonna take it for diagnostics on monday.

Did you guys use an extension or something to get the nut off the solenoid, non of my tools are fitting just right to move my hand. time to go to autozone

Mine did that, was the valvetronic motor £166 +vat main dealer.. 2 hour job plus new gasket £397 inc vat

I took it to a local garage today. The diagnostics showed a misfire had occured on cylinder 2. Unfortunately i forgot to ask for the excact code. They deleted to error code to see if it made a difference and when i took it for a test drive it seemed ok again for a while so i decided to leave it at that until there was a problem again. So driving back from the garage the light came up again at hard acceleration. What's interesting though is that now it disappears after restarting the car but before i had the fault code deleted, the light came up immediately after starting the car absolutely every time. I wonder if it could really be the valvetronic motor? I also found some sort of fix for a common fault in with the valvetronic motor: http://mhhauto.com/printthread.php?tid=1744

I used a regular 10mm socket wrench with an extension.

Turns out it was just a faulty coil on cylinder 2. They will replace it on monday at the main dealer. Goes under a general recall warranty.

Nice DIY! So... what role do you guys think BMW's long OCI plays? IF any?

These VANOS Solenoids aren't that expensive - if one needs to replace them. ~$130ish.

I swapped/cleanned my vanos a few weeks ago along with an injector cleaner (Chevron) fill and my car's idle is very smooth now. Not sure if was due to the vanos swap or the injector cleaning...either way I am happy with results. Next is task is changing spark plugs.