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Home >> Hyundai >> 2004 >> Santa Fe Base, Automatic >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis (2.4L) (2 Of 2) >> DTC Troubleshooting Procedures >> DTC P0421: Catalyst System Efficiency Below Threshold (Bank 1) >> General Information >> DTC Detecting Condition
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General Information: DTC Detecting Condition

DTC DETECTING CONDITION CHART

Item Detecting Condition Possible cause
DTC Strategy
  • Frequency ratio (Rf) of front and rear oxygen sensor used
  • Leakage in the exhaust system
  • Faulty Catalyst Converter
  • Faulty HO2S
  • Faulty PCM
Enable Conditions
  • Closed loop
  • Load value 25 < Ec < 70%
  • Engine speed < 2900 rpm
  • Idle "off"
  • Vehicle speed > 2.5 kph (1.55 mph)
Threshold value
  • Frequency ratio (Rf) of front and rear oxygen sensor > 0.918
Diagnosis Time
  • 150 sec once per driving cycle
MIL On Condition
  • 2 driving cycles
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