Volvo Repair: failed emission test, volvo 850, 400 bucks

Question
the code P0410 secondary air injection system. the car is 1996 Volvo 850. what is the problem, and is it expenses to repair. when the light first went on I took it to auto zone they did a reading and told me it was the gas cap

Answer
Thats what happens when Autozone attempts to think they are Volvo Wizards.  I wouldnt take my lawn mower for them to look at.  Secondary Air is most likely going to be an Air pump and airpump relay.  Its about 400 bucks.  I would take the car to a real Volvo shop, and if you need help finding one, I would be glad to point you in the right direction.  Roger