What causes a fuel pump seal to activate the Check Engine light, opt to replace

the fuel pump tank seal is $5.29 at NAPA(PART # AFP E8748S).the fuel pump assembly has to be removed from the tank to remove the old seal,then in with the new seal!>>> who/what told you to replace that seal? the fuel pump assembly for your vehicle is around $1000.00 and i hope you don't need it!