Mercedes Benz

P0455 is a diagnostic trouble code (DTC) that indicates the Evaporative Emission Control (EVAP) system has detected a large leak. The EVAP system is designed to capture and store fuel vapors from the fuel tank, preventing them from being released into the atmosphere. When the ECM performs a self-test and detects a significant leak in the EVAP system, it triggers the P0455 code. The most common cause of a P0455 code is a loose or faulty gas cap. However, there are other potential reasons for this code, including: 1. Faulty or Loose Gas Cap: A loose, damaged, or missing gas cap can lead to a large leak in the EVAP system. 2. EVAP System Hoses and Lines: Cracked, disconnected, or damaged hoses or lines in the EVAP system can cause significant leaks. 3. EVAP Purge Valve: A malfunctioning EVAP purge valve may not close properly, leading to an excessive leak. 4. EVAP Canister: A damaged or saturated EVAP canister can result in a large leak. 5. EVAP System Pressure Sensor: A faulty ...