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Home >> Kia >> 2012 >> Optima SX >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Control System Diagnosis (3 Of 3) - 2.0L >> DTC P2251: O2 Sensor Reference Ground Circuit Open (Bank 1/Sensor 1) >> Inspection Repair >> Component Inspection
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Component Inspection

  1. Inspect the front HO2S for any silicon contamination. This contamination will be indicated by a white powdery coating and this will result in a bad false voltage signal.

    If contamination is evident on the HO2S, replace contaminated sensor with the new one and go to next step.

  2. Is sensor contaminated?

    YES 

    • Substitute with a known-good HO2S and check for proper operation. If the problem is corrected, replace HO2S and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.

    NO 

    • Check for poor connection between PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
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