Control Circuit Inspection

Ignition "OFF".
Disconnect HO2S connector.
Ignition "ON" & Engine "OFF".
Measure voltage between Heater Control terminal of the HO2S harness connector and chassis ground.
Specification : 4-5V

Fig 1: Measuring Voltage Between Heater Control Terminal Of HO2S Harness Connector And Chassis Ground
Courtesy of KIA MOTORS AMERICA, INC.

Fig 2: Identifying Oxygen Sensor (B1/S1) And PCM Connector Terminals
Courtesy of KIA MOTORS AMERICA, INC.
Is voltage within the specification?
YES
- Go to "COMPONENT INSPECTION " procedure.
NO
- Repair 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.