[pituala]

Originally Posted by @Art_Mighty

If you look at the system, mechanically it's very simple. These types of valve timing systems are widely used by Subaru and Porsche (and maybe others) and from what I understand they are very successful with it.

What's missing in the drawing are the sensors for the crankshaft, timing cam and the ECU but the principle in it's operation is easy to understand; 1) the ECU commands a timing change by sending a signal to the oil control valve, 2) the oil control valve releases additional oil to hydraulically advance or retard the cam position, relative to the camgear 3) the ECU measures the change with sensor feedback. When the sensor input on the timing cam deviates from what the ECU is expecting, we get out lovely error code.

The amazing thing about the issue is that appears at random, both in which engines are affected and WHERE in the engine it happens. The different codes each represent a different cam:

P0016 Crankshaft Position Abnormality - (Bank 1=Passenger Side, Sensor A=Intake Cam)
P0018 Crankshaft Position Abnormality - (Bank 2=Drivers Side, Sensor A=Intake Cam)
P0017 Crankshaft Position Abnormality - (Bank 1=Passenger Side, Sensor B=Exhaust Cam)
P0019 Crankshaft Position Abnormality - (Bank 2=Drivers Side, Sensor B=Exhaust Cam)

My 1st theory for the root cause has to do with those oil passages in the block that go in-between the oil control valves and the cam gear. Either A) something is getting in there, B) something is being left behind or C) (in the cases multiple repair attempts have failed) the channel is blocked or barely passable to oil because of a defect in the casting process. If B&C are true, there may be problems with the casting process for this new engine (entirely plausible with it being so new), resulting in "bad" engine blocks.

A&B would explain why replacing all of these oil control valves and cam gears is working. Whatever is getting into in those channels is damaging these two parts so their replacement resolves the problem.

My 2nd theory for the root cause is there might be some sort of spring set that's faulty in either the cam gear, the oil control valve (or both) which return these critical parts into a middle or "neutral" position. If a spring malfunctioned then the system might be starting out in a state that's unacceptable to the ECU and that would also trigger the DTC

Yeah I get all that and I'm fully aware of how the CVT systems work as I've had much experince with them in a Nissan I used to own, but like you say unless something like a spring for oil valves is failing (seems unlikely to me unless there was a bad batch of metal, but that seems unlikely to me as well). If the oil passages are too narrow, then like I said before, why would it work fine for a certain random time then suddenly fail. And if it debree, gosh I gotta say how could something like loose casting flash not get caught at some point in the factory. All three possibilities seem unlikely when taking into account the "clean" factories that parts are built/assembled in.

The sensor idea is what seems most likely as I see electronics having a higher probability of failure as compared to something mechanical. Its hard to say as we're all just making educated speculations.

But hey, I could be completely wrong...