Chevrolet 2009 Express Owner's Manual page 26

Q:
What is wrong with this?
A:
The belt is twisted across the body.
1-22
CAUTION:
{
You can be seriously injured by a twisted belt. In a
crash, you would not 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/retailer to fix it.