There's some 03 Matrix info in softcopy.
Madstyle has hosted a lot of it at
http://madstyle1972.com/Repair/ and although the page is titled "2003 - 2008 Toyota Matrix OEM Repair and Wiring Manuals" he doesn't seem to have the wiring info, or at least I don't see it.
I already have some of that though, so I've attached the PDF from the 03 Matrix manual for "engine control" It covers both the base 1ZZ and the GT/XRS's 2ZZ engines, any differences are tagged with *1= 2ZZ, *2 = 1ZZ (yeah, I know, seems like they would have reversed that to get it line up)