Overview #

Diagnostics in CAN-based systems allow engineers, service tools, and applications to monitor system health, read data, and interact with ECUs (Electronic Control Units). Instead of just listening to raw CAN traffic, diagnostic protocols define structured ways to:

• Read fault codes (DTCs) – identify and interpret stored error conditions.
• Monitor live data – such as sensor values, status information, or actuator states.
• Run tests or control functions – e.g., trigger actuators or perform self-tests.
• Reprogram ECUs – update firmware or parameters via the same bus.

Live ECU Data #

Tapping into the diagnostic channel on a CAN network allows you to monitor live vehicle data. Oftentimes you can monitor more data than what’s visible on your Dashboard. V-Link uses this approach to send diagnostic requests to the CEM and retrieve the values.