TSB: Some 2021 ? 2023 model year Toyota vehicles may require the download and installation of vehicle specific software or configuration software when the Electronic Control Unit (ECU) is replaced. Techstream software has been modified to indicate when configuration software is required. A new Configure column has been added to the Techstream Health Check Results screen to show when configuration software is available for a specific ECU. Follow the Operation Procedure in this bulletin to complete the ECU Software Configure Process.