I think that Klaus hit the nail on the head. Go over to www.volvousa.com and look under owner library section. It will tell you what you have to do to run through the drive cycles. If you disconnected your battery recently or you replaced any sensor, your car will most likely have to go through these before it is ready. I would try that before inadvertently replacing an air pump. Just check your gas cap. You should be able to tell if the rubber gasket in it is damaged in any way. I mentioned it but from the code you're getting, I'm starting to doubt it and lean towards what Klaus had to say.
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.