Final answer:
Accessing an OEM data hub typically means that you are connected to the truck data bus, which is essential for interfacing with the vehicle's electronic systems. It doesn't necessarily mean you are connected to a data bus MID, viewing FMIs, or are online, although the latter may be required for web-based data services.
Step-by-step explanation:
If you have accessed an OEM data hub, it implies that you are interfacing with a system that allows access to vehicle-specific data provided by the original equipment manufacturer. Typically, accessing such data would indicate that you are connected to the truck data bus, which is the network within a vehicle that facilitates communication between various electronic control units (ECUs).
A data bus MID (Message Identifier) refers to components within the data bus, but simply accessing an OEM data hub does not ensure that you are connected to a specific MID. Viewing FMIs (Failure Mode Indicators) may be a part of the diagnostics or information extracted from the data hub, but it is not a necessary condition just for accessing the data. Being on-line could relate to having internet access, but again, this is not a requirement to be considered true just by accessing an OEM data hub. However, you would likely need to be online if the OEM data hub is accessed via web services, or remote data tools.