CSS J1939 DBC File

Decode Heavy Duty Data (PGN and SPN Database)


The SAE CSS J1939 DBC file contains decoding rules for converting raw J1939 data to ‘physical values’ (km/h, %, …). This lets you easily decode data from heavy duty vehicles (trucks, buses, tractors, …).

DBC is a CAN database format used in most automotive tools, include our CAN software/APIs.

Key Features

What is a CSS DBC file?

A CSS DBC file is a standardized method for storing the “rules” on how to interpret raw CAN bus data. In particular, it contains details on what ‘signals’ (e.g. RPM, Vehicle Speed, …) are contained within which ‘messages’ (i.e. CAN IDs).

CSS J1939 standard, messages are referred to as Parameter Group Numbers (PGN) and signals as Suspect Parameter Numbers (SPN).

CSS DBC file includes names, descriptions, positions and lengths of the signals, as well as how to offset & scale them.

DBC File

CSS DBC file download includes:

  • An SAE J1939 DBC file with ~1800+ PGNs and 12000+ SPNs
  • CSS J1939 Digital Annex Excel file (with additional PGNs/SPNs and description details)
  • One legal license (1 user, 1 PC) matching the DA license

When is the CSS database useful?

J1939 protocol is used across most heavy-duty vehicles, including commercial trucks, tractors, transit buses etc. Because the protocol is standardized, you can use the J1939 DBC file to decode data across the majority of heavy-duty vehicle brands, models.

CSS Database

What PGNs are in DBC?

  • Convert raw CAN IDs to PGNs
  • Convert PGNs to raw CAN IDs
  • Check if the PGNs are in the DBC

Technical Specifications

General Table