Standard OBD2 Fault Codes

On-Board Diagnostics (OBD) codes, universally applied across all vehicle manufacturers, are standardised to simplify vehicle diagnostics. These codes, known as Data Trouble Codes (DTC), enable easy identification of vehicle issues through OBD Scanners.

This guide serves as a tool for finding and understanding the OBD codes in vehicle diagnostics, streamlining the process of identifying and addressing your vehicle fault.

Code Format

Example: P0251

First Letter: Identifies the system related to the fault.

P: Powertrain (engine and gearbox)
C: Chassis
B: Body
U: User network

Second Digit: Indicates code type.

0: Generic (standard across brands)
1: Manufacturer-specific (not included in this guide)

The Last Three Digits: Specify the fault, using a hexadecimal format (0-9, A-F).

Powertrain (P) Codes:

0-2: Air/fuel mixture
3: Ignition system
4-9, A-C: Includes auxiliary emissions to hybrid propulsion

Chassis (C) Codes:

0-2: Wheel and axle dynamics
3-5: Brake system
6-8: Suspension and steering systems
9, A-C: Safety systems, including airbags and seat belts

Body (B) Codes:

0-2: HVAC (Heating, Ventilation, and Air Conditioning)
3-5: Interior features, including instrument panel and seat controls
6-8: Exterior features, including lighting and wipers
9, A-C: Security systems, including locks and anti-theft system

User Network (U) Codes:

0-2: Network and vehicle integration
3-5: Telematics, including GPS and internet connectivity
6-8: Proxy and remote function control
9, A-C: Diagnostic systems and communication errors