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HOMESERVICE MANUALSKIA2015FORTE LX, AUTOMATIC TRANSREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM DIAGNOSIS (1 OF 2) - 1.8LDTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1)DTC INFORMATIONDTC DETECTING CONDITION
2015 Kia Forte LX, Automatic Trans

DTC Information: DTC Detecting Condition

2015 Kia Forte LX, Automatic TransSECTION DTC Detecting Condition
Item Detecting Condition Possible Cause
DTC Strategy
  • Check catalyst oxygen storage capacity by evaluating downstream O2 sensor fluctuations
  1. Exhaust gas leaks
  2. Faulty rear HO2S
  3. Faulty three way catalyst converter
Enable Conditions
  • Coolant temperature >68°C (154°F)
  • 837°F < Modeled catalyst temp < 1700°F
  • Vehicle speed >25mph
  • 1200< Engine speed <3300
  • 0.22g/rev.< Mass air flow <0.9g/rev.
  • Ambient pressure >70kPa (700hPa)
  • Canister load <0.5
  • Lambda control active & Stable driving condition
  • Downstream O2 sensor operative readiness
  • No opening/closing of Canister Purge Valve
  • 11V < Battery voltage < 16V
Threshold Value
  • Average malfunction index > 1
Diagnostic Time
  • 50 Lambda Controller Cycles
MIL On Condition
  • 2 Drive Cycles
RENDER: 1.0x

NO RELATED

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.