I have a 2009 Mini Cooper base N12 engine manual. I purchased this from the original owner with around 80k miles and a cracked piston, previously wrote about the repair a couple of years ago. My son managed to overheat this and threw a piston and rod through the front of the engine right into the cat... and fyi, I discovered an oring lodged in the thermostat housing that was preventing it from operating properly. I suspect it was the oring on the outside of the plastic pipe connecting the thermostat housing to the water pump based on size that probably got dropped during the original repair and just took awhile to take the car down.
In any event, I purchased a new block and head out of the scrap yard, rebuilt, everything new and updated, and figured I was safe. About 80 miles later, the car ate a valve seat. I would be easy to blame on the head, but was probably a piece of metal I failed to clean out of the intake that eventually got through to the combustion chamber and hit the valve seat in just the right spot.
Took my original head, checked it out, new seals, cleaned it up. Changed a piston out that had been destroyed when the valve seat went through the top of the piston, thankfully did not harm the block, and back in business. Car runs!
Car ran great, except for a P0012 code that immediately showed up - like so many others have experienced. In reading articles, most of them are from people with a generic code reader. Hoping to add some details to assist for anyone having the same trouble.

Lots and lots of details to follow here, if you prefer to read the last chapter of the book first, or just want the Cliff notes version, skip below to the next post for how it turns out... I have gotten so much out of this website, I am happy to post some serious detail on a problem that anyone driving an older Mini will eventually face. I hope you find it useful and apologies in advance if its too much detail!

The car is running with these errors just fine - nice smooth idle, and when I reset codes right before the CEL, its zippy and seems to run without issue. Maybe a little low on power? When CEL sets, bam, definite reduction in power, but still accelerates and drives ok, no stutter, no idle issues. No smoke, getting 36 city - 40 highway mpg when driving conservatively. I only burn premium (91 octane, left coast) from major brands. No quickee marts.

For starters, P0012 and its sister P0011 are generic codes that report the engine is out of time - specifically the intake or exhaust cam adjusters are at their idle state in the wrong position, or fail to give the proper range when the VANOS solenoids are activated. The N12 engine has adjusters on both the intake and exhaust, unlike the turbo version that only adjusts the intake. There is a dwell adjustment on the intake only in this generation that allows the engine computer to change the amount of time the valve stays open which can also influence this code if there is a timing problem near the threshold. A BMW code reader makes a HUGE difference in troubleshooting this issue. So here is my troubleshooting process and what I did to clear this error.

Due to a departure from the Mini world, in an attempt to get GDIS working for troubleshooting my Chevy Volt, the device drivers for my ISTA software dumped and I was working initially with just a generic code reader. BIG *** MISTAKE.



Here is what can possibly affect either side of the timing equation - and I am specifically referring to generic P0011 and P0012 codes. P0016, P0017 I believe adds another dimension that is not totally covered here.

1) Timing chain - when it stretches, its possible for the angles of the intake and exhaust camshaft to be off such that the car is out of timing slightly. Since the two camshafts are only ~ 7" apart, and the timing chains generally only stretch a tooth over the whole length of the chain, this is far less likely the culprit than several other issues. Since the chains are cheap, once you determine its time to fix these issues, its worth replacing if over 60k miles or has been abused by overtemps or hard driving. In any event, a stretched chain is much more likely to give a crankshaft to camshaft correlation error, not the P0011/P0012, so we move on.
>>> I reused the original chain when rebuilding, then ended up replacing the chain twice, just in case, with a used chain that measured good, then a new one, and had absolutely no impact on this issue. Shop manual section 11 31 051 for replacement, 11 31 540 for checking elongation, and forgive me, I do not recall the acceptable length of the timing chain, but my original was 1.6 mm longer than the new one which measured dead on the shop manual value.

2) Timing chain upper guide - these things are a plastic guide snapped onto an aluminum bracket held on with two teeny tiny screws. They wear out, they bend, they break. They're $12. When they are really worn, it can influence the angle difference between intake and exhaust camshaft by 3° and if you want the math, Ill post it. When they break, the difference is more than doubled. If there is any doubt, just replace it. Dont use a used one. The guide will have a direct bearing on this issue, likely the P0011 error which is exhaust side. It should not affect the intake timing.
>>> In my case, the unit that came out of the car originally was in really good shape - I replaced it anyway, and as expected, no affect on the timing.

3) Timing chain tensioner. This one is beat to death, and truthfully could only have a minor impact on the relationship between intake and exhaust - when the engine is spinning, there is usually more tension on the exhaust side, but it is possible to have some slack between the two camshaft adjusters. More than likely though it will manifest as a crank / cam correlation code, pretty much right before your pistons meet your valves up close and personal.
>>> I always start with a new tensioner, and at $35, why chance it. This was not my issue

4) Timing chain sprocket, crank bolt - this is the chain sprocket located on the crankshaft and drives the camshafts through the timing chain. In all the Mini's I have rebuilt, no matter how bad the engine I have worked on, pistons going through the side, bottom, head, I have never seen one of these damaged. They cant spin on the shaft since they are sandwiched between the oil sprocket (which is pressed against the end of the crankshaft) and the crank hub for the vibration damper. Worse case, I have seen major engine failures because a PO tried to re-use the crankshaft bolt (hey, its a big bolt, I'm sure it will take it). Do not ever re-use this bolt - they hold tension by being overtorqued and intentionally stretched, which reduces their strength but increases their hold. While under tension the FIRST time, they will hold that tension beyond the life of the car. Once released and re-torqued, they lose their work hardening and will eventually fail! I tried to find a study that showed the reduction in strength, but alas, no data. They cost $9 at any dealer.
>>> Bolt part number is 11217616164, and I replaced. You have to take this apart to replace the timing chain and / or guides. Being desperate to find a solution, I did use a new timing chain sprocket, and as expected, absolutely no difference in symptom. Its part number is 11217534654, superseded by 11217588996 about $25

5) Timing chain guides - It seems no matter how carefully I replace these, I always manage to break the end of the right guide. Right = front of engine = exhaust side. Doesnt seem to make much of a difference. I have torn engines down and found these cracked or destroyed. A severely worn guide will likely not have any effect on this issue since it doesnt change the relationship between the two camshafts. If these are damaged, and your car is still running, you probably have correlation errors and some gnarly chain slap / death rattle. The guides are not horribly expensive, but do require some mild disassembly of the belt drive and removal of the crank hub / vibration damper, but really not a bad job. Around $33 for both guides.
>>> I started with new guides, and reinspected upon changing the timing chain, and no effect on the errors.11314609483 (exhaust side guide) 11317533879 (tensioner side guide)

6) Intake and Exhaust camshaft sprockets, otherwise known as Timing cam sprocket, VANOS adjustment sprocket, etc. I have rebuilt several Minis and had a bunch of these lying about, so here are some part numbers to assist in identification. Note the intake sprocket is the same on the S model and base -N12/N14, and clearly the exhaust is unique to the N12 as the turbo model has a simple chain sprocket. .
Intake or inlet = 11367545862, and they are marked with IN35... V754586280
Exhaust or outlet = 11367536085, and they are marked with EX30... V753608580
... and it goes without saying - when remounting these, do not re-use the camshaft bolts! see #4 above. The bolts are $6 at any dealer or online, part is 11367536087. Usually purchase online from Pelican/ECS.
The sprockets use oil pressure to rotate the outer portion, which has the teeth of the sprocket, from the center portion, which is firmly bolted to the end of the camshaft. I believe the numerical marking on the end of the adjuster gives its maximum rotation capability - seems to be right when I rotate on the bench, but someone can check me on that. 30° for the exhaust, 35° for the intake. Since they adjust in counter direction from each other, its really really really important to not mix them up.
They are not properly rebuildable without the factory tooling and setup - so suffice it to say that if you take them apart, its scrap as the spring unwinds, sometimes violently. There are tiny oil passages that can get clogged with shrapnel or sludge from running dino oil. Depending on how the shrapnel got in there, its possible they will not return to the correct position, or will not adjust to the full potential, or are just seized, which was the case for both adjusters in my original engine. These will definitely cause either P0011 or P0012 errors if damaged. I do not know of a good way to properly diagnose these on the bench, and usually rely on the error codes after I have eliminated everything else to test. Since these rely on good oil pressure, they may only be the symptom, not the problem!! See solenoids, and rings
>>> since these are really expensive, I reused some old ones that came off a head whose engine had overheated and the head was cracked, but otherwise had no timing errors. I have found online new OEM for around $125, which is what I ordered - see next post to see if it worked! Why did I order a new one? See below

7) VANOS solenoid - responsible for allowing oil pressure from the oil pump directly into the camshaft end and into the Camshaft Sprockets. If the solenoids go bad, and they do, assuming everything else is working, no adjustment from its associated cam sprocket. There are two solenoids, one mounted to the front of the engine and one to the rear. These are not horribly expensive online, around $65 for OEM, but I like to swap the exhaust and intake when troubleshooting assuming the problem is limited to one side. These solenoids are identical, and its an easy way to troubleshoot the problem. In a pinch, I have used an adjuster off my BMW M54 (or was it N52?) - they business end is close enough, and the connector is the same although its mounted 90 degrees but works in a pinch. They have metal screens on the oil inlet which can become easily clogged with debris. I was not careful on cleaning out one head after walnut blasting, and the intake solenoid was completely caked with walnut shells. If you pull yours, and find its covered in oil sludge, better to replace. Part number 11368610388, around $65 online, or brick and mortar, around $95.
I should also mention that if the electrical signal is not getting to the solenoid, you will get a symptom like the solenoid is bad but swapping the intake / exhaust solenoids will not solve the problem. The ECU pulses (PWM) the solenoid to allow intermediate values of adjustment depending on RPM, load, etc., and the system also does an open / short check on the solenoid and has separate codes for these. In theory, if there is a wiring fault, you should get an open circuit for that solenoid or possibly closed circuit fault. I had one N14 ECU that went bad, not on this car, and the MOSFET driver portion within the ECU was bad but the current sense was not - so the ECU was not reporting a bad solenoid or electrical fault as it could read the coil electrically, however, there was no output signal. Took me awhile to figure that one out. Took an oscilloscope to do it.
There is no option in my ISTA to activate a solenoid, but Im told in the original INPA(?) the text based one, you could activate a specific solenoid. Im also told it did not have a menu for the N12's, so that would be too easy- it would be possible to read the solenoid with just a volt meter. Since I know of no way to do this statically, you have to resort to using an oscilloscope to read the signals at the VANOS solenoid connector. I hacked apart an old VANOS solenoid, and clipped a pigtail connector of a junkyard Mini to make a simple breakout connector that I can measure with the solenoid in place and plugged in.
>>> I re-used the old ones and swapping them out had no effect. In the end, I just ordered a new one to see if that might be the issue. See next post.

8) Rectanrings - these are the rubber or metal rings with square cross section on the timing end of the camshaft that seal the oil chamber that feeds the camshaft sprockets pressurized oil from the VANOS solenoid. If that chamber does not hold pressure, you will get the P0011/P0012 among other errors. My rebuild kit came with metal rings, although the BMW parts system shows plastic rings are the correct part. Maybe someone can comment if they are interchangeable. Seems to me metal might be called for on the turbo and plastic on the base due to temperature service? Not sure. In any event it is easy enough to visually inspect for severe damage, i.e. a broken ring metal or plastic, but a worn ring is much harder to diagnose, so replacement is the option. The plastic rectangrings are part 11317587757, not sure of the metal part number. You need 4 of them, and it is possible to swap them out without disassembling the head - plenty of youtube videos on this. I also inspected the camshaft end bearing caps, which contain this oil chamber, for any signs of debris or anything that would keep the caps from mating properly - but they all looked good.
>>> I replaced mine, absolutely no measurable effect. I had metal on them originally, replaced with plastic. Mic'd them out to see if perhaps the metal might have worn a groove in the aluminum bearing / caps, but inspection looked good and no signs of serious wear.

9) Oil pump - low oil pressure? no adjustment, and you will see this usually at idle. It is often overlooked - and I replaced my oil pump with an OEM unit I purchased online during the initial. They are actually pretty easy to disassemble and inspect, but I did not want to take the time, so I just replaced mine while the block was apart. As I was troubleshooting, I did screw an oil pressure gauge, a cheapie I purchased from China Freight, to ensure I had good oil pressure at idle, which I did. You can easily measure by removing the oil pressure switch from the driver's side of the head and I used a brass adapter I purchased at home depot to connect the pressure gauge. Do not recall what pressure I had at idle, I believe it was around 10 -12 psi which is pretty good for a well used engine.I did change the oil, full synth 5w30, and should mention it was 118F in the shade when doing the test which likely resulted in the lower oil pressure. Low oil level will cause you issues! Procedure is in the shop manual section 11 40 000
[EDIT: I measured oil pressures by removing the oil pressure switch and checking on the side of the head. At IDLE cold, 58 psi, 1.5k rpm 62psi, 3k rpm 70 psi. Warmed up, idle 55 psi, 1.5k rpm 57 psi, 3k rpm 65 psi. I recall thinking - WOW I DID A GREAT JOB REBUILDING THIS ENGINE - AWESOMELY HIGH OIL PRESSURE. Shop manual does not give anything but a minimum pressure, which is substantially lower than this!]

10) Camshaft Position Sensors - two of them installed in the plastic valve cover, one for exhaust and one for intake. They read the cam 'gear' on the driver's side end of the camshafts that give timing signals to the ECU. If you have a bad sensor - i.e. it is electrically open or not reading, the engine will not start. Knowing a little about these type of sensors, I have read reports of people replacing sensors and fixing this P0012/P0011 - but Im calling BS on that one. If someone has direct experience with this, I would love to get my hands on the 'failing' sensor so I can measure it on a car. I will say I have seen a neighbor replace one, where the o-ring got stuck in the valve cover and they installed a new sensor with oring, and the sensor did not insert the whole way, but managed to seal . The car would run, stumble then as soon as it heated up car would stall, or it wouldnt start at all. On the original engine of my N12/R56, the head got so hot the valve cover warped, and the location of the camshaft sensor was actually shifted due to this, and Im sure it was giving some timing error codes as a result. In my case, I replaced the valve cover.
>>> I ordered a new sensor, but as expected, it had no impact on the error code. Swapping sensors changed nothing in reported timing or error codes.

10.5) Camshafts - added this after I was rereading, with all the accumulated auto parts in my shop, I though perhaps I got a turbo or JCW camshaft accidentally installed. Wouldnt that be nice. No such luck, but it took some investigation to cross reference the camshaft markings to the BMW part marking. Here are the numbers:
INTAKE: BMW / N12: 11317587755, marked with part V757707580-01, and "IN"
EXHAUST: BMW / N12: 11317587754, marked with part V756542080-02, and "EX"

11) Timing tools - this one probably should have been at the top of the list. But hey, unlike me, you always read all the instruction first, right?
I had a timing set purchased on ebay, that required lots of grinding and filing to fit. Sound familiar? As I was initially troubleshooting, I re-installed the timing tools to check proper cam alignment, and noticed the exhaust side bracket from the timing tool set would not seat properly with the cylinder head causing about a 2-3° error in timing. When I first had the P0012, it was accompanied after awhile by P0011. After purchasing an OEM grade timing tool set, the P0011 went away, and I was left with P0012. I ended up purchasing the AST Assenmacher MC1216 tool kit which fit tightly and right on the money out of the box. Even the crank lock pin fit tightly and properly out of the box.
A couple of quick notes on installing the tools - since there are no external marks from the factory on the crank pulley, I used a helper to rotate the engine to where the pistons are flat - i.e. in the 90° position, all level. Then I used a cheap dental mirror, purchased from home depot or china freight, to view the top bell housing access hole and slowly turned the engine looking for the hole. If you do not find the access hole, it is possible you are off by 180 degrees. It is so critical that you do not counter rotate the engine while lining this up - so I marked the position on the crankshaft with a piece of tape, then rotated clockwise again stopped just as the hole in the flywheel was evident in the access hole, and inserted the crank access hole. Press down, slowly slowly turn the crank and bam the tool will slide in. If you miss it on the first try (or second third fourth) have patience - this can definitely cause correlation errors betwen crank and cam if you are tempted to counter rotate the crankshaft while setting the pin.
The camshaft side will be much much easier to align if you have a narrow 27mm open end wrench. I use a large wrench set purchased from one of the box stores, but its waaay too thick and does not fit on the camshaft while trying to fit the camshaft lock. I ended up machining a wrench out of some scrap 1/4" aluminum plate and use for this purpose. A stamped metal wrench I have seen online will probably be better. If your camshaft alignment tools are not sitting flat, stop and fix the problem!

12) Diagnostic tools - as I mentioned at the top, my ISTA was not running and I relied on a generic tester. After 4 rounds of changing components, spent time and re-installed the software, and wow - new codes.
Generic reader = P0012
ISTA = 0x2870, 0x287D AHA
002870 = DME: VANOS, inlet, adaptation stop. "'A' CAMSHAFT POSITION - TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 1)", "VANOS INTAKE: ADAPTATION, LIMIT POSITION"
00287D = DME: VANOS, inlet: actuator movement. "VANOS intake: ACTUATOR MOVEMENT"
I used the BMW fault code lookup at bmwfault.codes to shed a little more light on these errors

There is a calibration setup within ISTA to set the camshaft dwell motor adjustment "Valvetronic limit position" - which I ran, and this dramatically improves idle. This sets the motor position on the camshaft dwell time adjustment. Unlike other cars (VW/Audi) which can do the adjustment without factory tools, you have to use ISTA or equivalent to set. If you know a way to do it without, please let me know!!
[** edit - there are monitoring functions within ISTA and activations within the same area, but none allow you to activate the VANOS solenoids, at least not in my flavor]
There is also a VANOS adjustment that verifies the maximum camshaft adjustment range and loads new PWM values from the solenoids. I.e. it checks operation at idle, where most of the adjustment occurs, and tests various driving duty cycle / PWM waveforms at the adjuster to find the right driving conditions to give proper adjustment. It returns maximum adjustment for both intake and exhaust and expects the range to fall within certain values. I believe you MUST run this after changing VANOS solenoids to account for differences in coil impedance and mechanical operation. For the N12:
VANOS Exhaust Calibration: 40 - 60° range accepted, target is 50°, my car is right at 51°, so good
VANOS Intake Calibration: 140 - 160° range accepted, target is 150°, my car is consistently 128° ... and the reason for the error codes immediately after clearing DTC.

I will note these values persist after swapping my two VANOS solenoids, replacing the rectangrings, swapping the inlet camshaft adjuster with another (believed to be good) adjuster, checking and rechecking timing alignment.

Considering the two errors - really looks like my camshaft adjuster on the intake is the culprit, just a question now if it is truly a mechanical fault within the adjuster itself, which will soon be rectified by swapping the new one in, or a mounting issue, oil pressure issue somewhere else within the head.
So... I sit with a running car, CEL, and having ordered brand new OEM
Camshaft Sprocket
VANOS solenoid
Camshaft sensor

and I will post update after I get these installed. If there is no update within a few days of this post, it means I replaced these components, which did not fix the issue, and decided to roll this thing off a mountain without me in it.

ISTA Error codes 2870 and 287D

Yep, it even ran with this hole in the side.

Dont let 16 year olds drive your car.

Intake camshaft adjuster

Exhaust camshaft adjuster

 

New camshaft position sensor, new intake camshaft sprocket, new VANOS solenoid installed, engine retimed.

No difference.

Verified VANOS solenoids are both receiving signals.

Stumped.

 

Man that was a Big Bang!

You seem like you have literally done everything that could be the cause.

Ate you on the mini2.com forum? You might ask mike1967 there. He's a wizard with these things.

 

Follow up -
I hope this helps anyone that is experiencing this trouble and managed to make it through my wordy posts.

One month and 3500 miles later... I have performed no additional work in that time, just driven the vehicle with this fault.
I started the car yesterday - voila, no CEL, performance returned to normal.

If I failed to mention in the original post, the engine I used came from a parts yard car that was not wrecked - never a good move. I note the oil pump was out of that car and looked clean. While I took the pump section apart and cleaned (it was nearly pristine), I did not verify the check valve, which I now believe was stuck closed causing oil pressure to be too high and perhaps opening the VANOS solenoid on the intake side without being signaled to do so. Likely over time the debris worked its way loose and the check valve started working as normal allowing the pressure to be regulated.

I have now driven the car several times, no codes active and power is back to normal. I do not plan to open the engine up, but I suspect anyone having this trouble and is certain the engine top end is ok may want to measure oil pressures (mine measured ~50 - 55 psi at idle) and try changing the oil pump to see if that clears their issue. Or try driving from West coast to Denver and back again to see if that magically fixes it.