For your case, you need to check the impact sensor first to remove the fault. Usually the impact sensor is located in the engine and the seat. It is suggested you consult with Volvo to confirm it.

                  It's behind the B-pillar interior trim usually sensor needs replacement or use sensor simulator at connector typically 1-3 ohms. If that doesn't cure it you'll need to access restraint module disable system and unplugged check wiring to sensor connector from control unit including looking for someone's splice from an accident possibly wired incorrectly.