Signal Circuit Inspection

Ignition "ON" & Engine "OFF".
Measure voltage between signal terminal of HO2S (B1S2) harness connector and chassis ground.
Specification: Approx. 0.4~0.5V

Fig 1: Oxygen Sensor (Down) - Circuit Diagram
Courtesy of HYUNDAI MOTOR AMERICA
Is voltage within the specification?
YES
- Go to next step as below.
NO
- Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NOTE: HO2S must have a clean air reference to function properly. The air is obtained by way of the sensor wire(s). Do not attempt to repair the wire(s), connector, or the terminals.