[TurDonor]

It could be a lot of things, but most likely not too bad. The VVT system uses oil pressure to change the timing, and this pressure is controlled by the oil control valve, OCV, which turns the electrical signal from your ECM into an oil pressure signal for the VVT controller. The P0012 code is meant to be a monitor for the right-side OCV. It can get clogged on the oil side or malfunction on the electrical side, it's not hard to access and test, it's right under the air intake stuff on the top of your engine.

Other things can throw the P0012 code though. A jumped cog on the timing chain for one, more of a pain to access, but easy to fix once you do. Or the whole VVT timing gear unit on the front end of the intake cam could be shot, even more of a pain and most expensive of the problems. But I would expect and hope for the OCV first, especially since you're running fine still. Plus, I think the VVT assembly generally fails to a P0011 code, although I'm not completely sure of that.

Let us know what you find.

 

[TurDonor]

Good news. Could be a little oil blockage in the OCV triggered the code then worked its way out. Good luck!