CVS? hmm...still need more info, what does it stand for.

Do you mean Cannister Vent Shut valve?

If that's the case, it's still way overpriced, the part is only like $50, see if you can do yourself, there might be a TSB out for it. If not, find a different mechanic to do it, should only charge you like 2-3 hours labor rate (depending on location and how much crap the mechanic has to remove to get to it).

Go to the dealer and have him (or her) print out these TSB for ya and see if you can do it yourself:

1) 03-001, JAN 03, Emissions/Engine Controls - MIL ON/DTC P1457 (EVAP)
2) 01-011, MAR 01, MIL ON - DTC P1457 Set
3) 99-075, OCT 99, Updated Troubleshooting - DTCs P1456 and P1457
4) 99-074, AUG 99, Troubleshooting DTCs - P1456 & P1457
5) 98-045, JUN 98, DTC P1456 & P1457 - Troubleshooting Update