Core Diagnostic Framework

A. Onboard Diagnostics (OBD-II)

• Standardized system present in all U.S. vehicles (post-1996)

• Interfaces via a 16-pin diagnostic port

• Retrieves:

  • DTCs (Diagnostic Trouble Codes)

  • Freeze frame data (snapshot at time of fault)

  • Live sensor data

B. Types of Diagnostic Trouble Codes (DTCs)

• P Codes (Powertrain) – engine, transmission

• B Codes (Body) – airbags, lighting

• C Codes (Chassis) – ABS, steering

• U Codes (Network) – communication failures