[framesliderz]

Wanted to share my experience with the community on how I have solved this common issue (at least for now). 2008 BMW X3 E83 3.0i N52. 221,000 km. So I ended up getting the OBDII code P0015 and BMW specific code 2A87 (exhaust camshaft over-retarded). Much research across the interwebs resulted in this distilled list of steps that made that code go away. What I've edited out are the trial and error steps to get to final resolution meaning this took a lot longer than what it would appear so hang in there if you attempt this. It's DIY and since I didn't fire the parts canon at this I'm not out of pocket (except the oil change but I needed that anyway). Here goes:
1-changed engine oil and filter by going to the stealership and getting the oem stuff (about $120 CAD). Didn't want this to be a variable.
2-pulled both exhaust and intake vanos solenoids out. Performed the 9V battery test on them to ensure I could see the solenoid plunging action happening. Gave them a good douching of brake clean. Dried them thoroughly and put them back in the engine block but swapped the positions (ie intake is now exhaust and exhaust is now intake). 10mm retaining bolt, watch for the o-rings and make sure you keep the wire connectors going to the correct solenoid
3-pulled both exhaust and intake camshaft sensors (inverted E8 torx socket). I noted that the intake sensor, aside from having some oil on it was fairly clean. The exhaust sensor, however, had a thin film of metallic wear particles. I'd say that's normal wear and tear but considering the sensor is 'hall effect' ie magnetic-based, getting rid of the metallic skin arguably helped. Same as vanos solenoids, I swapped intake to exhaust and exhaust to intake
4-here's the interesting part....after making sure no oil leaks popped up from the swapping of devices I would still throw the 2A87 code but less frequently ie every other day vs getting it the same day after code was cleared using Bluecat or generic BT ELM327 and Torque Pro. Also keep in mind it's summer so ambient temp is high 20s low 30s and 60%+ humidity. Drum roll....
5-a little more research and I performed the accelerator pedal reset. Turned the ignition to position 2 where the dash Christmas lights come on (ie key on engine off), stepped on the gas pedal right to the floor and timed the hold down for 30 seconds. When time elapsed I cranked over the engine until it started. BTW I did not turn the key off after the 30 seconds - just started the engine straight away. Let it idle for half a minute and then turned the engine off. Started it again and let it run a minute and then off.
What do ya know....I've been driving now for several days and no codes while in the same environmental conditions.
Hey, it's a BMW and it's long in the tooth but I give 'er the TLC it needs while crossing fingers. Still runs like a champ. Hope this helps like this community has helped me.

EDIT: a little over a year later...
...the saga continued
6-still kept getting 2A87. One behaviour I noticed was after driving the car at least up to operating temp, parking for say 10 mins (errands), restart and idle at a red traffic light, the engine would surge from an idle of about 700 up to about 2000 RPM and immediately drop back down to idle all while I had the brake depressed. That was a sure sign I was about to throw the code. Something about the engine having gone through a heat soak cycle would typically cause this to happen. There was another post (I think it was a 2007 X3) that hinted at a similar behaviour (can't find the link) but no final solve
7-at this point I went deep into refreshing several engine parts to permanently fix this issue (DIY) as follows:
-replaced bearing ledge exhaust and teflon rectangrings. Upon inspection there were only scuff marks left by the steel rings, no grooves. Frankly, that was a surprise. By far the most expensive part. I'll chalk this up to 'peace of mind' that it was performed.
-replaced eccentric shaft sensor (was weeping oil up into the connector)
-replaced exhaust side lifters (discovered one of the lifters was squishy all the rest were firm; no more ticking sound)
-replaced spark plugs and coils
-replaced valve cover (original was cracked and JB welded as a band aid solution)
-replaced starter (amazing how fast the engine cranks over now)
-replaced exhaust side vanos solenoid (aftermarket - I know, I know...)
-replacement bolts and gaskets where necessary (eg camshaft bolts, throttle body and intake gaskets etc)
-cleaned the vanos check valves (mine were clean)
-had to purchase timing tool and eccentric spring tool (amazon - about $300 total) < these tools are essential and honestly, the investment is worth it compared to a visit to a mechanic (or stealership)
-made sure the oil filter cage was still in good shape along with the 2 o rings (they were)

In the end, no more engine surges or 2A87. I will always wonder if I could have saved myself $1000 of the $3000 to do everything above but I certainly did not want to dig into the top end of the engine again like this. Another retrospective thought is if I had to do this all over again I would start with replacing the exhaust side vanos solenoid. In my case cleaning and swapping that solenoid did not solve (as noted at the beginning). Admittedly I did buy an aftermarket (URO) solenoid and in this case with success. Everything is refreshed and I intend to drive this great machine for as long as I can.

[Desh0923]

Hey man having the same issue here,I just wanted to know how the vehicle was driving before you did the reset
I have the same code and no low end torque at all

[framesliderz]

Originally Posted by Desh0923

Hey man having the same issue here,I just wanted to know how the vehicle was driving before you did the reset
I have the same code and no low end torque at all

I had no power issues prior to the reset (among a bunch of other adaptation resets). Just wanted all the learning algorithms to start from scratch based on all the new hardware.