Signal Circuit Inspection

Check for short to power in harness
1. Ignition "OFF"
2. Disconnect HO2S sensor connector and PCM connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 2 of sensor harness connector.
  Specification: below 0.5V
  
  Fig 1: Measuring Voltage Between Terminal 2 Of Sensor Harness Connector
  Courtesy of HYUNDAI MOTOR CO.
5. Is measure voltage within Specification?
  YES
  - Go to "COMPONENT INSPECTION " procedure.
  NO
  - Short circuit to battery between HO2S harness connector and PCM harness connector.
  - Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
    NOTE:
    In case, when HO2S harness connector disconnected, the output voltage at terminal 2 is 12V.
    
    Possible cause: Short circuit to battery in harness between E/R-J/BOX and terminal 2 of HO2S heater.