[lox]

Hey guys. Got a 2016 BMW M235i (N55) here, low on power/throttle response.

Getting error code: "135808 - Valvetronic servomotor position sensors, electrical, open circuit, shortcircuit: Malfunction".

Followed the test plan in ISTA+ which suggested to check and replace the servomotor and/or wiring harness.

So far I've replaced the servomotor (which has the built in hall effect position sensors) and checked continuity of wiring harness back to DME (pin 1 to pin 1, pin 2 to pin 2, and so on, as well as pin 1 to pin 2, pin 1 to pin 3, and so on - so I'm fairly confident there are no breaks or cross-wire shorts inside the harness) - but still getting this error. No signs of water/oil ingress to harness.

Eccentric shaft seemed to move smoothly and easily when I replaced the servo motor.

Suspecting a faulty DME, but this is a big expense to follow through on a hunch. Not sure how much further I can take my troubleshooting before concluding?

[lox]

Interestingly, the same 135808 fault is still present even with the Valvetronic harness disconmected at the DME - this has to be a faulty DME surely?

[TANTON79]

Originally Posted by lox

Interestingly, the same 135808 fault is still present even with the Valvetronic harness disconmected at the DME - this has to be a faulty DME surely?

Any resolve to this issue? I have a 2011 N55 F25 X3 and same issue.
When the car is cold it has no problems until it warms up then the code pops. I can do the 20 minute relearn process but it fails around 250 cycles or so.

Thanks