DTC's, or Diagnostic Trouble Codes, are used by automobile manufacturers to diagnose problems related to the vehicle. They are how the OBD-II (in light duty vehicles) or J1939 (in heavy duty vehicles) identifies and communicates to technicians where and what on-board problems exist.
The first number in the DTC indicates whether the code is an SAE generic code (applies to all OBD-II systems) or is specific to the vehicle manufacturer. The remaining three numbers provide information regarding the specific vehicle system and circuit.
The Samsara vehicle gateway plugs directly into the OBD-II or the J1939 port of a vehicle and can thus relay any information regarding any DTC directly to the Samsara Dashboard. Furthermore, alerts can be triggered in the event that a DTC code occurs by using the "Vehicle Fault" alert.
An analysis of a typical OBD-II code is shown below: