I have performed some tests on my vehicle when installing LVCAN (with a CAN-USB interface and LVCAN on the same bus) and the LVCAN module made the CAN requests by itself (i.e. active mode). I am pretty much 100% certain it works in passive mode as well since it has the hardware capability to do so, but I haven't personally seen it myself. Maybe Teltonika staff might clarify this.
Hope this helps.