Check the Power Source Circuit

Disconnect the connector from the ESC control module.
Turn the ignition switch ON, measure the voltage between terminal 28 of the ESC control module harness side connector and body ground.
Specification : approximately B+
Is the voltage within specification?
YES
- Check the ground circuit.
NO
- Check the harness or connector between the fuse (10A) in the engine compartment junction block and the ESC control module. Repair if necessary.
  
  Fig 1: Checking Harness Or Connector Between Fuse (10A) In Engine Compartment Junction Block And ESC Control Module
  Courtesy of HYUNDAI MOTOR CO.