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Home >> Kia >> 2018 >> Optima EX >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis - 2.4L (3 Of 3) (Except HEV) >> DTC P2251-00: O2 Sensor Reference Ground Circuit/Open (Bank 1 Sensor 1) >> DTC Information >> DTC Detecting Condition
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DTC Information: DTC Detecting Condition

Item Detecting Condition Possible Cause
DTC Strategy
  • Electrical monitoring
  1. Poor Connector Connection
  2. Open in Upstream O2 Sensor Control Circuit
  3. Faulty Upstream O2 Sensor
Enable Conditions
  • Sensor pump current valid
  • Battery voltage higher than 11V and lower than 16V
Threshold Value
  • Pumping current (Vip)/Reference voltage (Vn)
  • Passive check

    Vn higher than 4.4V or Vip-Vg higher than 2.35V or Vip-Vg lower than -2.35V or Vn-Vg higher than 1.6V or Vn-Vg lower than -0.1V or Pump current higher than 11.5mA

  • Active check

    Vip-Vg higher than 1.2V and Vn-Vg equal to or lower than 1.2V
Diagnostic Time
  • 2.5s.
MIL ON Condition
  • 2 Driving cycles
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