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 the 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 initializes the flash reprogramming sequence.