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Home >> Kia >> 2014 >> Optima LX >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis (3 Of 3) - 2.4L (Except HEV) >> DTC P2251: O2 Sensor Reference Ground Circuit/Open (Bank 1/Sensor 1) >> Wiring Inspection >> Control Circuit Inspection
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Control Circuit Inspection

  1. Ignition "OFF".
  2. Disconnect HO2S connector.
  3. Ignition "ON", Engine "OFF".
  4. Measure voltage between VG terminal of the sensor harness connector and chassis ground.

    Specification :  Approx. 2~3V

  5. Measure resistance between VG terminal and other terminals of the HO2S harness connector.

    Specification :  Infinite

  6. Is HO2S display near the specification?

    YES 

    • Go to next step as indicated below.

    NO 

    • Repair open or short to ground in signal circuit 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.

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