If you go to Toyota USA's FAQ site,
http://www.toyota.com/help/faq.html , and search for "timing" you will get this page titled "Timing Belt and Timing Chain":
http://toyota.custhelp.com/cgi-bin/t...i=&p_topview=1 , shows that the 2000-2005 Echo in the US had a timing CHAIN, and not a belt.
There is no prescribed replacement interval for a timing chain. IF it were a timing belt, Toyota recommends every 6 years or 90,000 miles, whichever occurs first. See the the "Timing Belt Recommendations" page,
http://toyota.custhelp.com/cgi-bin/t...GltaW5n&p_li=#
You can also view your scheduled maintenance guide (usually called the "Passport to Performance") for your vehicle at
http://smg.toyotapartsandservice.com/ to see what other maintenance items (besides the timing belt) should have been performed and at what intervals.