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Home >> Kia >> 2019 >> Optima EX >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis (3 Of 6) (PHEV) >> DTC P0420-00: Catalyst System Efficiency Below Threshold (Bank 1) >> System Inspection >> O2 Sensor Inspection >> Check HO2S
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Check HO2S

  1. Visually/physically inspect the following conditions:
    • Ensure that the sensor is securely installed
    • Check for corrosion on terminals
    • Check for damaged wiring
    • Repair as necessary and go to next step
  2. Ignition "OFF"
  3. Connect KDS to Data Link Connector (DLC).
  4. Warm up the engine to normal operating temperature and let it idle.
  5. Monitor following parameters in "Current Data" with KDS.

    Specification:  Above 0.6V at idle

    G13163068Courtesy of KIA MOTORS AMERICA, INC.
  6. Is measured value within specification?

    YES 

    • Fault might be intermittent and caused either by poor contact in connectors or wiring harness, or it has been repaired and control module memory is not cleared yet. Thoroughly check terminal of battery, all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
    • Repair or replace as necessary and then go to "VERIFICATION OF REPAIR " procedure.

    NO 

    • Carefully re-do this troubleshooting guide steps.
    • If no problems were found with the circuits or connectors, Replace the Three-Way Catalyst Converter and then go to "VERIFICATION OF REPAIR " procedure.
CAUTION:
  • Note that internal damage may occur when the component is dropped or mis-treated.