CAN Bus is the communication network built into most commercial vehicles. When a telematics device connects to it, the device can read live data directly from the engine and instruments – fuel consumption, RPM, odometer reading, fault codes – not just GPS position.
This is significantly more detailed than plugging into the OBD-II port. OBD-II only exposes standardised diagnostic data. CAN Bus gives access to the full set of manufacturer-specific operational data the vehicle actually generates.
Use OBD-II for light vehicles where quick plug-in installation is the priority. Use CAN Bus for HGVs and buses where data depth matters.
- FMS (Fleet Management System) profile – the standardised CAN Bus interface for trucks and buses, covering fuel, mileage, axle load, and door status
- Engine fault codes – exact DTC codes appear in the fleet platform as soon as the vehicle ECU logs them
- Idle time – recorded from ignition status and RPM, more accurate than GPS-based methods
- Fuel accuracy – consumption calculated from injector data, not estimated from speed