Macbook Pro M.2 SSD external check
You can connect a harddisk (also SSD) with another mac via thunderbolt or firewire. It will see it as external harddisk so you wont need to remove it from your macbook. 

How to run a other macbook as external harddisk:


Connect the two mac's with thunderbolt to thunderbolt OR firewire to
firewire
Power on the mac which has the harddisk you want to check and hold T to go to 'Target Disk Mode'. 
The harddisk will be shown as external harddisk, run it with disk
utilities to check the disk.


Check for more info the Apple support page