Just like the title says it’s not always, but it seems it is. G37 comes in for codes P0011 and P0021 not always will it be a cam phaser. Majority of the times it will be the gallery gasket. Rarely have I seen cam phasers go out on these VHR’s. These motors rely a lot on the gallery gasket to hold oil pressure. So always be sure to diagnose the car before you go out and buy parts that may not have nothing to do with the issue.