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HOMESERVICE MANUALSKIA2015FORTE EXREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM DIAGNOSIS (1 OF 2) - 2.0LDTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1)COMPONENT INSPECTION
2015 Kia Forte EX

Component Inspection

2015 Kia Forte EXSECTION Component Inspection
  • Rear HO2S (S2) Check 
    1. S2 visual check
      • Check assembling state of S2. (Check the interference between sensor wiring and exhaust pipe.)
      • Check corrosion, contamination, or damage on sensor terminal and connector.
    2. Is there something wrong?

      YES 

      NO 

      • Go to "CATALYST CONVERTER CHECK  " procedure.
  • Catalyst Converter Check 
    1. Catalyst converter visual check
      • Check discoloration by over-heating.
      • Check deflection or crack (hole).
      • Check noise.
    2. Check whether the catalyst converter is genuine.
    3. After erase the DTC, drive the vehicle more than 60 sec. according to "Enable Conditions" (Refer to "DTC DETECTING CONDITION "). And then, confirm DTC.
    4. Is there something wrong?

      YES 

      • Substitute with a known-good Catalyst Converter and check for proper operation. If the problem is corrected, replace Catalyst Converter and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.

      NO 

      • Many malfunctions in the electrical system are caused by poor harness (es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage. So, check poor connections and the related circuit between ECM/PCM and component thoroughly. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
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.