# P0420 vs P0430

Source: https://obdlens.com/compare/p0420-vs-p0430/
Last built: 941ad311c197960f285f

[Diagnostic knowledge](https://obdlens.com/knowledge/)

P0420 and P0430 have the same catalyst-efficiency definition, with a different bank. Compare the scoped reference wording before using either code.

| Reference family | P0420 · Bank 1 | P0430 · Bank 2 |
| --- | --- | --- |
| BMW | Catalyst System Efficiency Below Threshold | Catalyst System Efficiency Below Threshold |
| Continental Synerject Easy U | Catalyst System Efficiency Below Threshold Bank 1 | — |
| Ford | Catalyst System Efficiency Below Threshold (Bank 1) | Catalyst System Efficiency Below Threshold (Bank 2) |
| Acura / Honda | Catalyst System Efficiency Below Threshold | Front Bank Catalyst System Efficiency Below Threshold (Bank 2) |
| Genesis / Hyundai / Kia | Система катализатора, эффективность ниже порогового уровня (ряд 1) | — |
| ISUZU | Catalyst operating efficiency below threshold - Bank 1 | — |
| Dodge / Mitsubishi | Catalyst System Efficiency Below Threshold (Bank 1); Catalyst deterioration | Catalyst System Efficiency Below Threshold (Bank 2); Catalyst deterioration 2 |
| Infiniti / Nissan | Catalyst System Efficiency Below Threshold (Bank 1) | Catalyst System Efficiency Below Threshold (Bank 2) |
| Generic OBD2 | Catalytic converter system, bank 1 - efficiency below threshold | Catalytic converter system, bank 2 - efficiency below threshold |
| Belgee / Geely / Proton | Catalyst System Efficiency Below Threshold (Bank 1) | Catalyst System Efficiency Below Threshold (Bank 2) |
| Dacia / Renault | Низкая эффективность каталитической системы C-029 | — |
| GAC / Lexus / Toyota | Catalytic Converter System Bank 1 Efficiency Below Threshold | Catalytic Converter System Bank 2 Efficiency Below Threshold |
| УАЗ | Эффективность нейтрализатора ниже допустимой нормы | — |
| Audi / Jetta / MAN / Seat / Skoda / Volkswagen | Catalyst System Low Efficiency | Catalyst System Low Efficiency Bank 2 |

Bank 1 is the side containing cylinder 1. Bank 2 is the other side on V or flat engines; inline engines have only Bank 1. For exhaust oxygen sensors, Sensor 1 is upstream, closest to the engine; Sensor 2 is downstream, after the catalyst.

[P0420](https://obdlens.com/codes/p0420/) · [P0430](https://obdlens.com/codes/p0430/) · [P0135](https://obdlens.com/codes/p0135/) · [P0141](https://obdlens.com/codes/p0141/) · [Brand references](https://obdlens.com/brands/) · [Pending, stored and permanent codes](https://obdlens.com/knowledge/pending-stored-permanent-codes/)

## What is the difference between P0420 and P0430?

P0420 and P0430 have the same catalyst-efficiency definition, with a different bank.

## What does P0420 mean?

Catalytic converter system, bank 1 - efficiency below threshold

## What does P0430 mean?

Catalytic converter system, bank 2 - efficiency below threshold

Reference-family membership is not proof that a code applies to every listed ECU or vehicle. Runtime-ready definitions are not physical-vehicle validation. Unavailable readings must not be treated as zero. App and hardware sale availability must be checked separately.

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Reference-family membership is not proof that a code applies to every listed ECU or vehicle. Runtime-ready definitions are not physical-vehicle validation. Unavailable readings must not be treated as zero. App and hardware sale availability must be checked separately.