Replace/upgrade FA20 FB20 oil control valve vvt

How to change the variable cam timing control actuator on a Fa20 timing chain boxer engine brz/frs/gt86/forester/legacy/wrx. If you have a check engine light on for oil control valve, change the oil first, then Try updating to 2015-2017 or newer part. Then reset the check engine light and if it comes back, drive car for additional 2 weeks to a month and the learn value should adjust and your light will go off. Worst case you need a reflash of ecu (to reset all the self learn values) or new sprocket.