On my 2004 Tacoma,

The e-brake dummy light has come on...Does anyone know what has caused this? Could it be that I need brake fluid (according to owners manual)? That doesn't make sense to me seeing as though e-brakes are mechanical...

If it is brake fluid, can I simply add some or will that cause air in the lines on something this new???

I do appreciate your time.

there is a sensor on your master cylinder which turns that light on when the fluid gets too low you can add fluid right into the master cylind without any worries of air, also i would check all your lines and your pad/shoe thickness brake fluid doesn't disappear for no reason either theres a leak or low brake pads/shoes