i have a 2001 and it gets about 39-42 mpg
http://pdftown.com/2000-2002-Toyota-Echo-Service-Manual.html
The 2002 Toyota Echo OBD 2 port is under driver side dash next to kick panel
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.
The EPA mileage estimate for the 2002 Toyota Highlander is 19 mpg in the city, 25 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Prius is 42 mpg in the city, 41 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota 4Runner is 15 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Sienna is 17 mpg in the city, 23 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Camry is 21 mpg in the city, 30 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Tundra is 15 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Sequoia is 13 mpg in the city, 17 mpg on the highway.