http://pdftown.com/2000-2002-Toyota-Echo-Service-Manual.html
Stick your head under the dash and look up, sort of near where the driver's left knee would normally be.
For my 2002 Echo it is 3.7 Liters with a filter change.
3.6 liters
To flush the coolant in a 2002 Toyota Echo you will need to drain it first. Flush with fresh water and then refill with coolant and distilled water.
It's electronic.
See related link.
i have a 2001 and it gets about 39-42 mpg
See related link.
See related questions.
It is conveniently located inside the fuel tank :)
http://groups.msn.com/Sorensonbrian/frontbrakepads2002.msnw