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Home >> Kia >> 2023 >> Telluride EX X-Line >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnosis (8 Of 13) >> DTC P0420-00: Catalyst System Efficiency Below Threshold (Bank 1) >> DTC Information >> DTC Detecting Condition
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DTC Information: DTC Detecting Condition

Item Detecting Condition Possible Cause
DTC Strategy
  • Check catalyst oxygen storage capacity
  • Exhaust gas leaks
  • Faulty rear HO2S
  • Faulty catalyst converter
Enable Condition
  • Engine coolant temperature is greater than 55.5°C (131.9°F)
  • Catalyst temperature model is between 486.9°C (908.42°F) and 930°C (1706°F)
  • Vehicle speed is faster than 20 km/h (12.5 mph)
  • Engine RPM is between 992 and 3392 RPM
  • MAF ranges from 0.36g/revolutions to 1.8g/revolutions.
  • Barometric pressure (BARO) is greater than 75 kPa
  • Canister load is lower than 0.65
  • Fuel trim is active
  • Lambda set-point is between 0.96 and 1.04
  • Stable driving condition
    • Difference absolute-value between engine RPM and filtered engine RPM is lower than 200 RPM
    • Difference absolute-value between air mass and filtered air mass is lower than 0.45g/revolutions
    • Difference absolute-value between lambda and filtered lambda is lower than 7%
  • Downstream HO2S operative readiness is detected
  • No opening/closing of canister purge valve
  • Battery voltage is between 11V and 16V
Threshold Value
  • Average malfunction index is greater than 1
Diagnostic Time
  • 20 Fuel trim controller cycles
MIL ON Condition
  • 2 driving cycles