How do you reset radio 850 Volvo?

If the Word "code" appears, you need to punch in the 4-digit code that's probably on a card in the brown plastic container with your owner's manual in your glove box. If it's missing, call any Volvo dealer service department and ask for the radio code. They'll ask you for the VIN number of the car which is at the bottom of your windshield. Then they should be able to look it up. Once you have the code, just punch it into your radio to unlock it. You need to do this every time you remove or kill your battery.-Ricardo FuriOSo