Hyundai Repair: air fuel ratio gauge question, air fuel ratio, sensor side

Question
My 2001 Tiburon has four wires running to it. There are two white wires, one gray wire, and what appears to be a black wire. Which one would I connect the oxygen sensor wire to?

Answer
I believe the colors you list are on the oxygen sensor end of the connector.  These aren't shown in the schematic, so you'll need to look at the wires on the connector end of the sensor.  The schematic shows two red/white wires for the heater, a brown wire for the sensor ground, and a yellow wire for the sensor signal.  So you'll want to connect to the yellow wire (or the one on the sensor side that connects to it).