The brake fluid-level sensor sets off a warning on the dashboard (same warning lamp as leaving the handbrake set). But that signal also goes to the ABS and disables the ABS/TCS. The reasoning is if you're doing a handbrake turn the ABS & TCS don't interfere with it.

 

ok.. yeah so the mechanic put the sensor back in and the lights are not there anymore..
so I guess I'm fine and maybe I should just do the bleeding?

thanks for the explanation on why it sets the other ones off too