This manual pertains to Mitsubishi vehicles equipped with the 4D56 and 4M41 diesel engines. The 4D56 is a 2.5-liter inline 4-cylinder engine, while the 4M41 is a 3.2-liter inline 4-cylinder engine, both featuring Common Rail Direct Injection (CRDI) fuel systems. These engines are known for their robust construction and reliable performance, making them suitable for a variety of demanding applications. This service and repair manual focuses specifically on the Common Rail System HP3, a critical component of these advanced diesel powertrains. The purpose of this manual is to provide comprehensive technical information for technicians and mechanics. It covers essential maintenance procedures, diagnostic strategies, and repair instructions for the common rail system and related engine components. Detailed technical specifications, troubleshooting guides, and information on components such as the HP3 injection pump and common rail pressure sensors are included. By utilizing the information within this manual, qualified personnel can ensure the optimal performance, longevity, and safe operation of Mitsubishi vehicles equipped with the 4D56 and 4M41 engines.