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HOMESERVICE MANUALSKIA2015FORTE EXREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM DIAGNOSIS (1 OF 2) - 2.0LDTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1)DTC INFORMATIONDTC DETECTING CONDITION
2015 Kia Forte EX

DTC Information: DTC Detecting Condition

2015 Kia Forte EXSECTION DTC Detecting Condition
Item Detecting Condition Possible Cause
DTC Strategy
  • Check Catalyst Oxygen storage capacity

    (FTP75 HC or NOx emissions > 1.75*120kmi ULEV threshold)
  1. Exhaust system
  2. Downstream O2S
  3. Catalyst converter
Enable Conditions
  • 1300 RPM < Engine speed < 3000 RPM
  • 20 < Engine load < 75%
  • 600°C < Catalyst temp < 850°C
  • Fuel system status = Closed loop
  • Time after engine start > 260 sec.
  • Delta temp of Catalyst < 40°C
Threshold Value
  • Amount of Oxygen Storage < 30mg
Diagnostic Time
  • 4 Cycles of Lambda Set point steps (Rich to Lean)
MIL On Condition
  • 2 Drive Cycles

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

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

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

  • • You smell fuel, burning insulation, or see smoke.
  • • 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.