BMW Repair: OBD-II Code, bmw 323i 2000, obd ii code

Question
My BMW 323i 2000 model currently has check engine soon lights on & off, so I check with code scanner when it is on. Scanner code # is P1397. Description is camshaft position sensor "B" circuit (bank1).
Could you tell me what should I do ?
Thanks

Answer
Roger, Your engine has an exhaust camshaft sensor and an intake camshaft sensor. I don't know what sensor 'B' is considered. Please give me the last seven digit of your VIN. If you haven't replaced either of the cam sensors before then I recommend replacing both the intake sensor and the exhaust sensor (also related O-rings). The new sensors are of an updated style and I haven't seen one of the newer sensors fail. Both older style sensors will eventually fail.
-Evan