po496 code on 2005 Cadillac SRX

I asked car dealer about it, they said the one at the gas tank or the one in the motor compartment? how can i find the right one thats bad.when i remove the gas cap to fill up the car will not start unless i press on the gas padel.

Asked by for the 2005 Cadillac SRX
1 answer
that is why you pay for a diag to determine the failure. you can guess and replace parts but in most cases, guesses are incorrect and expensive.