ECM Update

[aghadden]

Hello, my 2005 XC90 V8 threw a CEL. Codes are p2407 and p2421. Both refer to evaporative emmision system. I repalced the fuel cap and reset. Light came back on. I have read that the vehicle may need an update to the ecm software to compensate for false trigger on aging systems. My question is what version of the ecm software is the correct updated version for my vehicle, and can I detect what my current version is using my OBDII scanner? If it is the software, I won't have to pay the $90, and if it is not the software, I don't really need the dealer to hook it up. My Stealership told me it is not stored in the VIN records. Is that BS? (I know Mercedes knows everything about our benz).

Also, any DIY instructions for replacing the pump if that is indeed the problem?

thanks