Toyota and Lexus ET640ML Firmware: Calibration Reference

ET640ML is a firmware identifier associated with Toyota or Lexus automotive software. The identifier alone does not reliably establish which control module uses it or what vehicle function the calibration controls.

Its exact application requires a complete calibration identifier, part number, catalog filename, or vehicle-specific service record. Those details can distinguish an engine or transmission calibration from software for another vehicle system and help identify any named stock or modified variant.