where is the evap. sensor relay on 09 silverado on 2009 Chevrolet Silverado 1500

I getting the code p0449 and going to try and see if a new evap. sensor relay will fix it but I'm not sure where it is I'm thinking it's by the gas tank. I'ts a 09 silverado ext. cab with a 5.3 Any help would be helpful. Thank you

1 answer
There is a TSB : SB-02-06-04-0371 issue date 2010-09-01 vent valve solenoid assem. replacement and filter box relocation. Call dealer for further details.

TSB= Tehnical Service Bulletin.... (this is not a recall)