Yeah best to take it to independent Volvo repair shop and let them read the codes with a ECC compatible reader. Call around and find a shop in your area that deals with A/C systems and ask if they can read the Volvo ECC codes for you and give you an estimate. What kind of problems are you having with the A/C system? I just did one that coded the power control relay, then I ran through the test as outlined in the Volvo shop manual to double check and sure enough that relay had burned out. It was about $100 to replace it but thats one of the cheaper fixes in the A/C system. Here's a link that helps explain late model ECC codes and what they mean : http://www.brickboard.com/FAQ/700-900/HeatingAirConditioning.htm#ECCClimateUnitDiagnosticCodes

Good luck.......... Mike