This manual covers the Hitachi EX270LC-5 Excavator, designed for demanding operational tasks. It encompasses various engine types, including ISUZU A-6BG1TQA, A-6BG1 TQA01, and HINO H07D, ensuring comprehensive support for different configurations. The EX270LC-5 is engineered for reliability and performance, making it a valuable asset in construction and heavy-duty applications. This document provides access to the same detailed information used by professional technicians, ensuring accuracy and completeness for all service and maintenance needs. The purpose of this manual is to provide detailed guidance for the maintenance, repair, and troubleshooting of the Hitachi EX270LC-5 Excavator. It includes operational principles, system overviews, component operation, performance tests, and in-depth troubleshooting sections. Furthermore, it details hydraulic and electrical circuits, connectors, and harness information, along with workshop procedures for the upperstructure, undercarriage, front attachment, and engine. This resource is intended to empower owners, mechanics, and technicians to effectively maintain and repair their equipment, saving time and reducing repair costs.