Howdy
I’ve got a 2011 n18 turbo r56 cooper s with some new trouble codes. I’ve got 130k and new coils recently.
it was running great until it got cold (20°f) I started it that day and it ran like garbage. Misfiring until it warmed up, then threw out a reduced power light.
codes:
2dce- valvetronic no adjustment possible
2d42 valvetronic stop not learned

Now that it’s warmed up I turned the valvetronic servomotor behind the head with a 4mm hex and it would start and run better after I cleared codes. Still in limp mode though, and once i turn it off and restart the car it will not start well and the servomotor goes to the position it started in (all the way out). If I adjust it again it will start fine. Sometimes it will run fine and keep a CEL on but not be in limp mode. I don’t think there’s any internal damage for this reason.

My thoughts are to replace the valvetronic servomotor first. I’ve heard I need to reprogram after doing this, but also heard it’s not necessary.

If that does not work I wonder if it’s a dme or programming issue.

I don’t have any of the bmw tools (inpa, ncs expert, etc) but my thoughts are to download those and get the cable to start using them. I could reset the cas and start there.

Does anyone have any ideas about where I should start? Or any other ideas as to the source of this problem?

 

On cold start, the N18 engine air control is done using the throttle plate valve in the throttle body. Once the engine warms up a bit the throttle valve goes to full open and the intake air management switches to variable intake valve lift. The point of variable intake valve lift is to eliminate the pumping loss at low RPM caused by the partially opened throttle plate. You'll see this if you have a boost gauge of monitor the intake air pressure, on cold start it will show vacuum which is the engine pulling against the mostly closed throttle valve. Then when the engine warms up and the throttle valve opens all the way the vacuum suddenly goes to 0 when the variable intake valve lift takes over.

The servomotor for the variable intake valve lift could be the problem, or maybe the throttle body, check both.

 

Thank you! I’ll check the TB as well.

 

Hi, I got same codes. Did you fix yours? Thanks.

 

yes. I went to the junkyard and found same year same motor same transmission car and took the valvetronic servo motor off of it. I cleaned it up and changed the spark plugs and it runs great now. Just search junk yards and find one, cost me less than $100. Just try to find one that someone changed the oil on, seems they wear because of sludgy conditions.