You may want to try rolling the diagnostic dice to help narrow down the possibilities :-)
https://www.youtube.com/watch?v=TSHzKOZ37iU
Or consider using this website to help you find a qualified service center to help you :-)
RepairPal Certified shops can diagnose and repair your 2005 Volvo S40. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.