Can't erase SSD on main bay
First, make sure it's not just a regular connectivity problem. I used to have an older MBP that displayed the same symptoms every now and then (with the stock HDD). Whenever it threw question-marks or missing file-system symbols at boot-time; I'd just pop it out, blow it like an old Nintendo cartridge, and pop it back in. If that's not the problem;




Make sure your AC adapter is plugged in and connected to your Mac.
Turn your Mac on, by hitting the power button, as per usual.
Press and hold:  ⌘ Command+R until you see the 
 Apple logo or the OS X Utilities.  
First off; you can try repairing and/or erasing your drive etc. via the Disk Utility.  
Finally; if all else fails, just select Reinstall OS X and follow the prompts.
The installer requires Internet Access. You can choose a network from the Wi-Fi Menu.
(top-right).