I can't Home Y

The printer is an Ender 5 Plus, I installed the BTT Octopus V1.1 board, TFT43 V3.0 display, TMC 2226 driver, Z axis is connected dual.The firmware is Marlin-bugfix-2.0.x, I compiled the firmware myself, but I'm a beginner. BLT performs a self-test when the printer is turned on. After pressing Home X, the extruder on the X axis stops at the end stop. After pressing Home Y, the axis moves 1 cm and stops and there is no end stop. After pressing Home Z, the extruder moves to the center of the X axis and the Y axis moves 15 cm to the end stop, but does not reach it again. 15 cm, when the Y axis moves, is independent where it is located. If the Y-axis is closer to the end stop below 15 cm, it will hit it and the Y-axis end stop will not stop it. I can't Home Y. Did anyone solve this problem?

Y stop is constantly triggered. May be a busted cable/switch, or the endstop is set the wrong way in the Marlin config.
Also sounds like the Y-axis direction is inverted. This means whenever you tell it to home, it assumes it is already homed (small jump and stop). It also means that whenever it has to move 15cm from home, then the home position will be wherever the carriage currently is.

The cable to enstop Y had a defective cable. now I can Home Y.