BMW Valvetronic operation on N42 engine (fault?)

***Please look through the comments for possible TIPS and FIXES for BMW N42 engine.***
***QUICK FIX in many cases - unplug Valvetronic position sensor!***
(Keep in mind that it is not a "real" fix, just a "hack", which nevertheless helps in many cases!)

*Original description:*
This is how the electric motor turns the Valvetronic eccentric shaft on a BMW N42 engine. The system has a fault, but I don't know yet what it is. The engine doesn't start with Valvetronic activated. It starts only when I disconnect the eccentric shaft sensor (near the oil cap). The behaviour in the video seems somewhat erratic, but I'm not sure if the fault actually manifests itself here. What do you think?

[ciprianungureanu]

Hello,
I think i have the answer for this problem.I have the same problem too.In my case the valvetronics block when engine is warm and doesn't work 'till the engine cools down
BMW says in the documentation for this engine that needs the ECU programmed for some engines (depends of the manufacturing period).I will try to do this, but i'm not sure if it works in all cases.
So..I have another hypotesis:
The excentric shaft bearings 11377615379 are damaged
If one of this bearings is damaged the actuator enters in protection mode (like the power windows motors)- the motor torque is bigger than the preset value (aka motor high current consumption) the ECU stops motor alimentation (exactly like if you stuck your hand in the window when you try to close the window).
So...if the lines, the DME valvetronic relay, the motor and the fuses are ok...this could be the only logical explanation-SHAFT STUCKED IN DAMAGED BEARINGS.

[Imantos]

No. I assumed that it was an eccentric shaft wear issue and permanently disconnected the eccentric shaft position sensor, which in effect left the engine in a constant limp mode. The car works OK, but it has less power, especially in low revs, and uses more fuel (~0.5 liters per 100km). I actually saw signs of wear on the eccentric shaft where the intermediate rocker body (not the roller!) touches the shaft. Still, I don't know for sure what the problem was.

[africanhistory]

Same issue (I think) I am not informed on cars. But my mechanic made me buy a sensor eccentric and he said he re set the vv motor on the computer and it is ticking like a clock now. Diagnosis shows sensor faulty.

[cibernetik]

To my e46 316ti the timmig was no more in position...and the most important thing to this motors by maxim 140.000 km you have to change the complet timming(chain with all the plastics inside), if not start to jump from his original point and finaly get the chain broken.sorry for my bad english.

[georgelambrogogle]

if you unplug the sensor, or disconnect the motor, doesn't that lock the eccentric shaft at whatever position the motor was last ? As you can see in the video, the motor moves the gear through different angles..What position should the gear / motor be at so that valvetronic is off ?

[cesartello]

Hola, es posible poner a punto sin la herramienta ?? por el tema del avance, qué no tiene chavetas. gracias

[ZeroInfinitives]

This is 100% Valvetronic motor fault. A common fault on these engines.

[hackam]

Hello, I hate N42.. I burned down one motor and after buying a new one which is used and replace, after one month I get the same problem like in the video. The mechanic has spent almost a 2 month to fix the problem without any success. Now, I look in the car I do not know what to do.. I remove the plugin from the sensor, and the engine is started...

[roshardsanchez]

how to adjus the valvetronic adaptation ?

[balintmihalyfi]

Hello,
I have the same problem on my BMW. Does anybody know how I can solve this issue? Change the valvetronic sensor/ECU/motor or something else? Thank you for your answer!

[arielkuska]

hi all, i have the same problem with my BMW, the engine fires burning as if on 3 cylinders, VALVETRONIC instantly opens up to the max after disconnecting the sensor further the same, only the same engine disconnect the engine burns valwetronic nomalnie, a dense that the valve open just a little if anyone solved the problem

[jonasschougaard]

if i unplug the valvetronic the car stop going in safe mode and i can start it but then it start burning way more fuel and the transmission light pops up. did that also happen to you?

[jonasschougaard]

where do I unplug the valvetronic position sensor? do anyone know of a video where it is done or do someone have any instructions. it would help me a lot if someone could send me a link of some video or instructions

[sudnut]

Have scanned the error codes with the sensor plugged in?

[maironvasquez]

Hello, I have the same problem, I can find out what the fault was?

[paulsaari]

Well you get this problem if you get oil sludge... and you have oil sludge

[MyKnifeBeLike]

how much hp do u get when the valvetronic is off?

[ahmedza]

did you fix it? what was the problem? vvt motor or sensor?

[andrhrstv]

Imantos what were the symptoms prior the car got to the point not to start?

[indiaLyricsurielhl]

I hace a 2859 DTC = valvetronic, eccentric shaft sensor: reference. And the engine doesn`t start