Check The Ground Circuit.

Disconnect the connector from the ABS control module.
Check for continuity between terminals 1,4 of the ABS control module harness side connector and ground point.
Is there continuity?

YES
- Check the wheel speed sensor circuit.
NO
- Repair an open in the wire and ground point.
Fig 1: Checking Continuity Between Terminals ABS Control Module Harness Side Connector And Ground Point
Courtesy of KIA MOTORS AMERICA, INC.