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Home >> Kia >> 2016 >> Optima SX Limited >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 108 (Engine Control System Diagnosis - 1.6L (2 Of 3) - Optima (Except HEV)) >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1) >> DTC Information >> DTC Detecting Condition

DTC Information: DTC Detecting Condition

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Item Detecting Condition Possible Cause
DTC Strategy
  • Check Catalyst oxygen storage capacity
  1. Exhaust system
  2. S2
  3. Catalyst converter
  4. Out of range ECT sensor
  5. Exhaust manifold
  6. High fuel pressure
  7. Incorrect connection
  8. Misfire
  9. Injector
  10. EGR system
Enable Conditions
  • Engine speed 1720-2800RPM
  • Engine load 21-63%
  • Catalyst temp (model) is greater than 500°C (932°F)
  • Fuel system status: Closed loop

    Purge factor (high load canister) is less than 12

  • Misfire not occurred
  • No O2 sensor error
  • No purge valve error
  • No fuel system error
Threshold Value
  • Mean difference between the amplitude of downstream O2 sensor signal and that of modeled signal is greater than 0.7
Diagnostic Time
  • 100s
MIL ON Condition
  • 3 driving cycles

* S1: upstream oxygen sensor/S2: downstream oxygen sensor

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