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Home >> Kia >> 2017 >> Cadenza Technology >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnosis (6 Of 6) >> DTC P2251-00: O2 Sensor Reference Ground Circuit/Open (Bank 1 Sensor 1) >> Component Inspection >> Check HO2S (B1/S1) performance
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Check HO2S (B1/S1) performance

  1. Ignition "OFF".
  2. Connect VMI to KDS/GDS and select "Oscilloscope".
  3. Ignition "ON".
  4. Measure signal waveform between Pin No. 1 (Nernst Voltage) terminal of HO2S (B1/S1) harness connector and chassis ground with VMI.
  5. Measure signal waveform between Pin No. 3 (Virtual Ground) terminal of HO2S (B1/S1) harness connector and chassis ground with VMI.
  6. Measure signal waveform between Pin No. 6 (Pumping Current) terminal of HO2S (B1/S1) harness connector and chassis ground with VMI.
  7. Measure signal waveform between Pin No. 4 (Trim Resistor) terminal of HO2S (B1/S1) harness connector and chassis ground with VMI.

    Specification:  Refer to Fig 1

    Fig 1: Scantool Display - Signal Waveform Of HO2S (B1/S1) At Normal Condition
    G12283971Courtesy of KIA MOTORS AMERICA, INC.
  8. Does the HO2S (B1/S1) operate properly? (Check variation)

    YES 

    NO 

    • Carefully re-do this troubleshooting guide steps.
    • If no problems were found with the circuits or connectors, replace the HO2S (B1/S1) and go to "VERIFICATION OF REPAIR " procedure.
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