Can't enter Apple Hardware Test Mode on my macbook pro
You can use the following terminal commands to determine the model and board ID of your computer:

sysctl hw.model | awk '{ print $2 }'
ioreg -l | awk -F\" '/board-id/ { print $4 }'


Then download the proper AHT from this link 

https://github.com/upekkha/AppleHardwareTest