OBD Modes

OBD Modes are different services provided by the ECM, such as clearing codes or monitoring live data. Manufacturers are not required to support all modes and they are allowed to create additional modes (manufacturer specific data). Each mode has is own unique identifier signified by $xx, where xx represent the hex identifier.  Each OBD-II mode is briefly described below:

  • Mode $01 – Request Live Data
  • Mode $02 – Request Freeze Frames
  • Mode $03 – Request Stored Trouble Codes
  • Mode $04 – Clear/Reset Stored Emissions Related Data
  • Mode $05 – Request Oxygen Sensors Test Results
  • Mode $06 – Request On-Board System Tests Results
  • Mode $07 – Request Pending Trouble Codes
  • Mode $08 – Request Control of On-Board Systems
  • Mode $09 – Request Vehicle Information
  • Mode $0A – Request Permanent Trouble Codes

We will take a more in depth look at each mode individually in later articles, where we will see the use of each mode’s identifier.