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Severity: LowKia

P0420 on Kia Vehicles

The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. P0420 →

87Complaints mentioning the code
#1Rank among 14 brands
14.1%Share of Kia DTC complaints

In NHTSA owner complaints we analyzed for Kia, P0420 was mentioned 87 times.

Most mentioned models

Kia Soul Ev45
Kia Soul36
Kia Optima2
Kia Sportage2
Kia Forte1
Kia Sorento1

Model years mentioned

Model years mentioned – Kia P04201077121113141423152116617218219
2007: 1 · 2012: 7 · 2013: 11 · 2014: 14 · 2015: 23 · 2016: 21 · 2017: 6 · 2018: 2 · 2019: 2

Components named in these complaints

  • Engine (75)
  • Fuel/propulsion System (20)
  • Unknown Or Other (15)
  • Power Train (14)
  • Engine And Engine Cooling (5)

Reports with a crash: 2 · fire: 2 · injuries: 1

Often appears together with

P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate P0303 Powertrain Cylinder 3 is misfiring. Check whether it misses at idle or under load before you blame… Moderate P0455 Powertrain The fuel vapor system can't hold vacuum at all — check the gas cap first, then hoses and valves. Low

Possible causes

  1. Catalytic converter worn out or poisoned by age, oil ash, coolant or silicone50%
  2. Rear (downstream) O2 sensor slow, contaminated or reading out of range15%
  3. Exhaust leak ahead of the rear O2 sensor (manifold, gasket, flex pipe)12%
  4. Engine fault that overheated the converter: misfire, rich mixture, leaking injector10%

P0420: Diagnosis step by step →

Related codes

KiaEmission ControlsCheck engine light onPoor fuel economyLoss of power P0420 · FordP0420 · HyundaiP0420 · Dodge

Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.