Engine Control Module (ECM) Control Relay: Notes
WARNING: This page is about a different car, the 2004 Hyundai Santa Fe and 2003 Hyundai Santa Fe. However, it is still accessible from the selected car via links, so may be relevant.
When the ignition switch is turned on, battery voltage is applied from the ignition switch to the PCM, turning ON the ignition power transistor and energizing the MFI control relay coil. This turns ON the MFI control relay switch, and supplies power from the battery to the PCM through the MFI control relay switch.