Have a 2004 Impala LS - and had the entire ABS mechanical module fail...
Message was displayed on screen.

Took it to our trusted local shop (vs dealer) and they ran all the tests, and found it was not functioning correctly. They offered to try installing a pullout vs a totally new module. Went that path, and it worked for about 6 months... then that one failed. Brought back, and they installed another pullout... and that is still going strong.

This 2004 Impala LS has had more maint than any other car we've owned....
- dash cluster gauges stepper motor problem - replaced entire cluster
- ABS module - failed
- auto rearview mirror - intermittent cabin down lights - loose wire/connection
- dual heater dash lights - one side burned out
- fog light lens - inside seam cracked, leaked water - just superglued over seam
- etc......