VVT and OCV replacement
 

So I got the old check engine light, vsc light, and traction control lights on. Ran it thru a OBD 2 scanner and got the P0012 error code. (Camshaft Position 'A' Timing Over-Retarded). My 2006 xB has about 105k miles on it.

Started small and hoped for just dirty oil causing the problem, so got an oil change and a flush, but the error code returned :(

So on to the next steps, checking for and possibly replacing a faulty variable valve timing (VVT) or faulty oil control valve (OCV)

How much should checking and possibly replacing these at the mechanic cost? Or, if I go a DIY route, do I need to drain the oil again to take out the VVT to check it?

Advice much appreciated, thank you!

VVT
 

You don't need to drain your oil, From what I hear its hard to accurately test it . Its easier to just replace it.

Sensor
 

Facing the front of the motor there is a Camshaft sensor on the right. Pull it out and clean it off with some brake cleaner and a Scotch Brite Pad. Mine looked like a piece of Caramel and was over doing the VVT. No need to drain oil.