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October 30, 2026 Service bulletin

Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated without replacing the...

Toyota technical service bulletin T-SB-0021-25 Rev1 for 2023-2027 Toyota Prius, 2023-2027 Toyota Corolla and 2024-2027 Toyota Tacoma and others.

Bulletin number
T-SB-0021-25 Rev1 (T-SB-0021-25 Rev1)
Component
Engine
Summary
Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated without replacing the ECU. Flash calibration updates for specific vehicle models/ECUs are released as field-fix procedures described in individual Service Bulletins. This bulletin details the Global Techstream+ (GTS+) ECU flash reprogramming procedures and outlines use of the Technical Information System (TIS) and the Calibration Update Wizard+ (CUW+). To ensure the correct ECU software is installed, ECUs will require a Security Signature before the ECU will initialize the flash reprogramming sequence. This bulletin also details the process for acquiring a Security Signature from TIS during the GTS+ ECU flash reprogramming process.

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