Retrieving Codes With Voltmeter

Before entering on-board diagnostics, refer to SERVICE PRECAUTIONS. Turn ignition off. Locate Data Link Connector (DLC), next to fuse block. Connect analog voltmeter positive lead to DLC MFI diagnosis terminal. See Fig 1 . Connect negative voltmeter lead to ground terminal.
Turn ignition on. Voltmeter will display trouble codes by sweeps of the pointer. Trouble codes will be displayed in numerical order. A constant repetition of short 12-volt pulses indicates system is normal. If any trouble codes exist, the voltmeter will display 12-volt pulses.
Codes will appear as long and short 12-volt pulses. Long pulses represent tens; short pulses represent ones. For example: 4 long pulses and 3 short pulses indicate Code 43. After recording fault code(s), perform necessary repair(s) to indicated circuit(s). See FAULT CODES.

Fig 1: Identifying Self-Diagnostic Connector (Elantra)

Courtesy of HYUNDAI MOTOR CO.