what causes the ABS light to come on? on 2000 Subaru Legacy

The ABS light came on after a sudden stop
and stayed on.

Asked by for the 2000 Subaru Legacy
You have a malfunction in your ABS system, the light means that there are fault codes in your ABS system Also as long as the ABS light is on, the ABS system is disabled, so you have no ABS braking, until the problem is repaired/resolved.

here are some shops: