No such light is documented on the Toyota dashboard light web site. Can you give us a picture? Are you sure it isn't just the "eco" light that tells you you are running in the "eco zone" of efficiency?
on page 12 of this PDF, http://www.toyota.com/t3Portal/document/om/OM47674U/pdf/sec_02-02.pdf (page 202 of the 2012 paper manual) The Maint Reqd light is physically near the Eco Mode light, so it may seem like you have a Eco Maint light. The Eco mode part just means you have pressed the Eco Button in the center storage unit. The Maint Reqd light just means you are approaching some multiple of 5000 miles, it goes off every 5000 miles. - http://www.toyota.com/t3Portal/document/om/OM47784U/pdf/sec_05-02.pdf
