GMC Denali 2004 Owner's Manual page 26

Q:
What's wrong with this?
A:
The belt is twisted across the body.
1-20
{
CAUTION:
You can be seriously injured by a twisted belt.
In a crash, you wouldn't have the full width of
the belt to spread impact forces. If a belt is
twisted, make it straight so it can work
properly, or ask your dealer to fix it.