Chevrolet 2004 Impala Owner's Manual page 341

Removing the Wheel Covers
Your vehicle may be
equipped with wheel
covers.
To remove the steel wheel covers and wheel nut caps,
loosen the plastic nut caps with the wheel wrench in
a counterclockwise direction. If needed, you can finish
loosening them with your fingers. The plastic nut
caps will not come off. Use the flat end of the wheel
wrench and pry along the edge of the cover until
it comes off. The edge of the wheel cover could be
sharp, so do not try to remove it with your bare hands.
Do not drop the cover or lay it face down, as it could
become scratched or damaged.
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