I don't have the manual for a 2000 volvo s70.

You have to turn the key to position 1 where the radio comes on but not your instrument panel. then leave it on this position for 2 hrs. the word "code" will come on instead of "off".Then you have to put in your 4 digit security code. to obtain this, call a volvo dealer and have them run your vin. they may ask for proof of ownership. if the radio has never been changed out, this will fix it for you! the radio says "code" if the battery was disconnected, and if the wrong code was punched in 3 times, it went to "off" :-) if you have difficulty, email me at savolvo at yahoo directly.