The ABS system has a microprocessor similar in function to the engine management system. When it turns on the ABS light that indicates that the microprocessor has detected an error in the "self test" functions and as a safety measure it turns off the ABS capability. In order to determine what failed you need to plug in a diagnostic tool into the ABS port and read out the trouble code and follow the repair procedures.
There is a method for retrieving the trouble codes manually and without a diagnostic tool and that is described here.
http://www.kiatechinfo.com. Please note that this is for U.S./Canadian spec left hand drive Sportages but it SHOULD be the same for right hand drive.
Having said all that chances are you have a dirty or defective ABS wheel sensor. But the trouble code readout will tell for sure.
Linear Mode
