How to access Diagnostics Menu programmatically or by any means other than physical touch key input?

I have a damaged screen digitizer. I have root access and USB debugging enabled, but I can't figure out how to invoke the diag menu via ADB shell. Any help?

 

I have it posted up on Android SE, but no responses.

On XDA I posted it up in the HH thread since there wasn't any other thread specific to automotive head units, but I think I'll just post it up as a new thread in General. Thanks!

 

I've already tried most of the input device scan codes enumerated in the various keyboard config files found on the head unit, but these only appear to invoke native Android functions rather than these touch key functions. Allegedly, all input devices should have a character map stored somewhere that dictates how each input key's scan codes will be interpreted, but I've yet to look further into that regard. As for the power key input, I believe they are referring to `keyevent 26` which on the head unit only toggles the display on and off, rather than being the equivalent of the Audio button.