Owners of a 2011-2012 Chevy Volt (built prior to Sept. 20, 2011) may complain about a rattle-type noise heard from the front of the vehicle at slow speeds over bumps.
The noise may simply be caused by the front brake pads rattling against the calipers.
Apply light brake pressure while reproducing the rattle. If the noise is eliminated as the brakes are applied, replace the front brake pads with the revised kit P/N 22799077.
The revised kit includes improved abutment clips.
If the noise does not go away, inspect the front suspension components.