That means that there is a hard fault in the abs system, from one of the 4 wheel speed sensors being faulty, yaw rate sensor faulty, faulty hydraulic unit or abs control module,, short in wiring harness, faulty wheel speed sensor reluctor ring.
The ONLY way to find out where the fault lies is to have the abs system scanned for fault codes using a diagnostic scan tool. Some parts stores will do this for FREE for you. If none in your area will, then you will have to take it into a shop to have this done.
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