Could you run a vent line up in the wall. That vent does not individually need to go al the way to the roof, it can intercept an existing one as long as it is at least 42" above the flood line of the other things on that vent.
Basically, you need the vent to come off of a line before it turns down into the main line, and, at least in most of the USA (don't know about Canadian codes), on a 2" pipe, that vent connection should be made within 5' of the p-trap.
The way you have it now, there is no way you could run a snake through that line, and it exceeds the maximum distance to the vent to pass codes in the USA in most code definitions.