I work at an independent shop that specializes in BMWs. Out of all the newer bmws we service, I would say N55 equipped cars are on the rare side at our shop. We've done mostly maintenance on them but the two cars that stand out both had catastrophic valvetrain failure. Of these two vehicles, one popped a rocker arm off, got lodged underneath the cam and sheared the center bolt for the VANOS gear on the exhaust cam and the other vehicle had the exhaust cam break in half shortly after it went to the dealer for VANOS bolt recall. This is just a little backstory on why I may be a little more paranoid than I should be with this 2011 335xi thats currently kicking my ass.

One thing I wanted to ask about, and my primary focus is throttle valve operation with valvetronic 3. I with most likely many others was under the assumption that the throttle valve was open all the time, or most of the time on vehicles with valvetronic. And when your stepping on the loud pedal you are actuating valvetronic motor and not necessarily the actual throttle valve. Well I've closely monitored throttle valve angle on this 2011 N55 and I think either,

A.) something in this system is faulty or

B.) It is a general misconception that throttle valve is open most of the time.

Cold start, hot start, cruising, idle and under load the throttle valve for the most part, directly correlates with my input of the gas pedal. I say for the most part because on cold start I've seen as high as 45% without stepping on the throttle ( which makes sense after starting the vehicle cold i.e high idle warmup) and when the engine is settling down at idle I see 3-5%.

With ISTA I can monitor throttle valve angle but the setpoint value it says "not available" I'm not sure this is normal for this car because I have no other identically equipped models to compare too. But usually if ISTA has a setpoint vs. Actual it will give you both. Could somebody maybe confirm this is normal for this car or I'm an idiot and the problem is staring me in the face the whole time?

Also with both ISTA and autologic I cannot view vanos adaption angle or eccentric shaft angle. Can anyone else view these values with their N55 with live data?. I understand with these vehicles and newer alot of live data is test plan driven, so I've been through test plans of both VANOS adaption reset and valvetronic limit learning and valvetronic teach in procedures and nothing is giving me a surefire value of what my eccentric shaft angle is or vanos adaption in degrees. I've searched everywhere and spent literally hours looking for this data with ISTA and autologic and I've got nothing.

This car has 59K is a 2011 335xi appears to be bone stock but the customer purchased it just before he brought it in and there's no service history.The fault I'm getting is 28AO-P112F code. Usually this is the ONLY fault it throws ( Throttle valve angle intake pipe pressure plausibility too high). The car runs and drives great maybe a tad slower than I would expect but it has a slightly lopey idle. Sometimes after clearing the fault it's hard to get it to set again I'll go through 5-6 drive cycles with the car still idling lumpy but it's hard to get it to set. Sometimes if it goes long enough it will set misfire codes on all cylinders, but plugs are recent and I know it's not just a set of ignition coils.

I've smoke tested, boost leak tested, removed throttle body and thoroughly cleaned, even popped off the cover to make sure there was no signs of oil or corrosion on the circuit board of the throttle body. I've replaced both pre and post throttle body MAP sensors, tested crank case vacuum at idle. This is a dry engine with no signs of front crankshaft seal failure. I've checked wiring from MAP sensors to DME and throttle valve to DME and everything checks out but I feel like there is a chunk of information just staring me in the face but with no similar vehicle to compare to I'm just not sure about the cause of this fault.

There is one oddball bolt on the intake to the turbo, where it bolts to the valvecover that maybe suggests the turbo inlet was converted back to stock. I'm not sure if maybe this car does have a flash or something and not sure how to check flash counter with ISTA although I haven't tried yet because I just thought of it.

I feel like I may be looking at stretched timing chains, or potential strange valvetronic issue. My suspicion is related to how Mini's with stretched chains and spun crank dampener pullies with throw "Air mass plausibility faults" instead of cam/crank correlation faults or camshaft senor faults.

Anyways if you've read this far, sorry and hopefully you have an exact car to compare these values too? Any advice is greatly appreciated.