On my Ender 3, it seems that the Y-axis can only move forward 220 mm after which the carriage will hit the tensioner. This seems repeatable so I don't think it's a hardware issue (unless it's expected that the nozzle can reach all the way to the front edge).
I'm unclear, with this information, how I can center my nozzle properly so that it is 117.5 mm from each edge, and that the corner leveling feature works as expected (by default, configured to be 30 mm from each edge).