CAN FD (Controller Area Network with Flexible Data-rate) is the faster evolution of the classic CAN bus, allowing larger data payloads and higher bit rates between vehicle electronic modules.
Newer vehicles increasingly use CAN FD for module communication. A diagnostic interface without CAN FD support simply cannot talk to those networks — a hardware capability, not a software update.
Why it matters
When buying VCIs or scan tools for late-model coverage, CAN FD support is a checklist item; its absence dates the hardware regardless of the brochure.
Related terms: VCI, DoIP, OBD-II · Related reading: Choosing a diagnostic platform