This service repair workshop manual provides comprehensive technical information for the Mitsubishi Forklift Trucks FB16KT, FB18KT, and FB20KT models, with a primary focus on their controller systems. These electric forklift trucks are engineered for reliability and efficiency in various material handling applications. The manual details specific controller variants, including those identified by serial number prefixes like EFB4A- and EFB5A-. It covers critical systems such as the drive, hydraulic, and fail-safe mechanisms, offering in-depth technical data essential for maintaining optimal performance and operational integrity. The purpose of this manual is to empower technicians, maintenance personnel, and owners with the knowledge required for effective service and repair of the controller system. It includes detailed procedures for inspection, adjustment, removal, installation, disassembly, and reassembly of controller components. Furthermore, it provides extensive troubleshooting guidance for malfunctions, alarms, and diagnostic codes, alongside comprehensive electrical system diagrams and wiring schematics. This resource ensures users can perform diagnostics and repairs with confidence, saving time and costs by leveraging factory-original information.