Mercedes Benz

OBD-II Trouble Code P0505 indicates a problem with the idle control system of the engine. The idle control system is responsible for maintaining the engine's idle speed and preventing stalling. When the engine control module (ECM) detects a malfunction in the idle control system, it will trigger the P0505 code and turn on the check engine light. Symptoms of this code may include an erratic or high idle, stalling, or difficulty starting the engine. The possible causes of the P0505 code include a malfunctioning idle air control (IAC) valve, a dirty throttle body, a vacuum leak, a faulty mass airflow (MAF) sensor, or a faulty powertrain control module (PCM). To diagnose and repair the issue causing the P0505 code, a mechanic will typically use a scan tool to read the codes stored in the ECM and perform diagnostic tests on the idle control system, including the IAC valve and the throttle body. The mechanic may also check for vacuum leaks and test the MAF sensor. Depending...