I am confused

I told you guys I received a code P0418 and the secondary air pump or smog pump was bad. It looks like in the manual there are two air pumps or smog pumps. How will I know which one to change out. I am confused about changing out the right one, my truck has 193500 miles on it and this is the only trouble I have had with this truck. My truck is a 2011 Toyota Tundra cab and a half with a 4.6 L engine in it. Can someone help in changing out the right air pump ? Please help me. Thank you.

 

Removing the air pumps is a package deal. They are both mounted to a bracket. It's easier to take out them both at once.

Once out, just apply 12 volts to the plug end. The pump that doesn't work is the one to change.

 

Ok that is what I need to know. Thank you for the help.