You do not need a scan tool for a 4S-FE. Use the diagnostic port:
Until today.
Do you have the from the ECU sticker? I can try to find the specific variant for that unit. 4E-FE ECU Pinout and Wiring Diagram | PDF - Scribd 4s-fe ecu pinout
When working with the 4S-FE wiring loom, three specific problems occur frequently: You do not need a scan tool for a 4S-FE
These pins receive data from the engine. A faulty connection here results in poor idle, check engine lights, or limp mode. check engine lights