There is 2 build sheets in C4
Top of gas tank,
Take off rear license plate
Remove pass side back-up light
Use flashlight to look to the right to top back corner of gas tank.
IF your build sheet is visible remove via pass side tail light.
If need be
Anchor tank strap firmly with vise-grips, or it will twist like a pretzel.
Go under car and carefully loosen tank strap with socket and ratchet until you can slip build sheet out from under
Or look at the backside of the front cross member under the power steering reservoir for a small hole (quarter size).
If you can see the build sheet it can be removed by twisting round and round with tweezers until it comes out.