What is meaning the DSA lamp when it is on? Does it mean the system is working or it is not?
Light on means it is not working. But that does not mean it's faulty, you may have accidentally turned it off. Here are some threads I will put is separate windows to make it easy to hyperlink: http://volvoforums.com/forum/volvo-s40-11/dsa-light-42738/
http://esd.volvocars.com/site/owners-information/MY08/S40/S40_owners_manual_MY08_EN_tp9154web.pdf ..Page 131 BEST ONE
Looking for a Used S40 in your area?
CarGurus has 981 nationwide S40 listings starting at $1,299.
Search Volvo S40 Questions
Volvo S40 Experts
Related Models For Sale
Used Cars For Sale