T The constitutional court is a judicial institution that has a vital function in maintaining the constitution and ensuring the upholding of the principles of the rule of law. in the case of violation of the code of ethics by anwar usman, the former chief justice of the constitutional court, there were deviations in the examination process by the constitutional court honorary council (mkmk), particularly during the preliminary examination stage which was conducted openly. in fact, article 26 paragraph (1) of pmk number 1 of 2023 expressly states that the preliminary examination must be carried out in private. the main problem in this study is whether the implementation of the examination is in accordance with the provisions of pmk number 1 of 2023 and what are the legal consequences of non-compliance with the preliminary examination procedures carried out openly. the type of research used is normative legal research and is descriptive-analytical, using secondary data with primary legal materials in the form of trial minutes, as well as secondary legal materials from legislation and legal literature. the data analysis technique was carried out qualitatively, with deductive conclusions drawn. based on the results of the study, it was concluded that there were procedural violations in the implementation of the preliminary examination by the mkmk, which has the potential to cause formal defects and weaken the legal force and legitimacy of the decision. therefore, full compliance with the procedures stipulated in the pmk is required as a form of protection of the principle of due process of law and to maintain the integrity of the constitutional court.