OBD Guide
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P0430

Catalyst System Efficiency Below Threshold Bank 2

P0430 is an OBD-II diagnostic trouble code meaning: Catalyst System Efficiency Below Threshold Bank 2. Common causes: wear or “aging” of the catalytic converter, misfires (unburned fuel destroys the catalyst). Estimated repair cost: $11–889.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$11–889 (est.)

Symptoms

  • Check Engine light is on
  • Rotten egg smell (hydrogen sulfide) from exhaust
  • Reduced power (with severe destruction)
  • Increased harmful emissions
  • Technical inspection failure
  • Rattling noise from under the car (when the catalyst substrate has crumbled)

Causes

  • Wear or “aging” of the catalytic converter
  • Misfires (unburned fuel destroys the catalyst)
  • Rich air/fuel mixture
  • Engine oil or coolant getting into the combustion chambers
  • Catalyst overheating
  • Using low-quality or leaded fuel
  • Faulty rear lambda probe (false code)

How to Fix

  1. Check for other codes: misfire (P030X), mixture (P0172/P0175) - fix them first
  2. Test the lambda probes: use an oscilloscope or scanner to check the behavior of the rear probe of bank 2
  3. Inspect the catalyst: knock on it - rattling indicates destruction
  4. Check the condition of the spark plugs and ignition coils of bank 2
  5. Conduct exhaust analysis for HC, CO, NOx content
  6. If ineffectiveness is confirmed, replace the catalytic converter of bank 2
  7. Reset the code and do a long test drive (minimum 80 km)

Related codes

P0420P0421P0422P0431P0432P0433P0136P0137P0156P0157

Error P0430 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0430 code mean?

P0430 is an OBD-II diagnostic trouble code that indicates: Catalyst System Efficiency Below Threshold Bank 2

What causes a P0430 error code?

The most common causes of P0430 include: Wear or “aging” of the catalytic converter; Misfires (unburned fuel destroys the catalyst); Rich air/fuel mixture; Engine oil or coolant getting into the combustion chambers.

How do I fix a P0430 diagnostic trouble code?

To fix P0430: Check for other codes: misfire (P030X), mixture (P0172/P0175) - fix them first. Test the lambda probes: use an oscilloscope or scanner to check the behavior of the rear probe of bank 2. Inspect the catalyst: knock on it - rattling indicates destruction. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0430?

Do not drive — repair immediately

How much does it cost to fix P0430?

The estimated repair cost for P0430 is $11–889. Actual cost depends on your vehicle, location, and labor rates.

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