i have error code 121 going to put new part in can i disconnect battery to clear old error code???????? as it seems easyer for novice like me.[&:]

 

You need to leave the battery disconnected for a bit with that method. You also need to have your radio anti-theft code unless you don't mind not being able to use the radio. If you don't have the code the dealer should be able to give it to you.

There is another method for clearing codes http://www.troublecodes.net/Volvo/ explains the other method which would probably be easier