What does P0420 code mean?

P0420 indicates catalytic converter efficiency below threshold. Common causes: O2 sensor failure, clogged/aged catalytic converter, engine misfire.

OBD-II DTC code format?

P0xxx (Generic), P1xxx (Manufacturer-specific), C (Chassis), B (Body), U (Network). The first letter indicates system type.

DTC Code Lookup Tool

OBD-II

OBD-II DTC decoder. Enter P0300/P0420 etc. for official definitions, DIY troubleshooting, and compatible parts. 9,400+ standard codes.

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SAE J2012 Standard · P/B/C/U Full Range

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DTC Detail

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OBD-II DTC database with 9,417 SAE J2012 standard codes, covering P/B/C/U full range.

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OBD-II DTC Code Classification

SAE J2012 Standard

P0-P3

Powertrain - Engine Standard

73 standard codes

Body System

300 standard codes

Chassis System (ABS/ESP etc.)

498 standard codes

Network Communication

1230 standard codes

Data source: (MIT) — SAE J2012 / ISO 15031-6Wal33D/dtc-database (MIT) — SAE J2012 / ISO 15031-6

Check Engine Light On? Here's What To Do

Don't Panic — The check engine light can mean anything from a loose gas cap to a failing O2 sensor.

Step One — Use an OBD-II scanner to read the DTC code. Enter it in this tool. Most repair shops read codes for free.

Step Two — Based on the DTC code, decide if it's safe to drive. Issues involving safety systems (ABS, airbag, steering) need immediate repair.

Step Three — Find matching parts on motuon.com. Most sensors, spark plugs, ignition coils, etc. can be replaced DIY.

⚠ Disclaimer: This tool is for reference only. For serious faults, contact a professional repair shop. Data based on SAE J2012 standards. Manufacturer-specific codes may differ.

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