P012 = "Intake Valve Cam Timing Over Retarded, Bank One"
$900 to replace the passenger side cam phaser, had it done myself awhile back. They'll try to clip you for $2,000 if you just take it in and say fix it. Get a written estimate on the cost to replace the passenger side cam phaser, should be around $900.
If you have the time and skill you can try it yourself, there are some posts on how to do it.