Toyota Prius Plug-In service engine soon message appears at startup, dealership unable to diagnose on Toyota Prius Plug-In

Some Toyota Prius Plug-In owners report experiencing a "Service Engine Soon" message at startup, indicating potential issues within the vehicle's systems that require attention. If the dealership cannot diagnose the problem, these owners often find it essential to pull diagnostic trouble codes to identify the specific issue triggering the warning. Additionally, some owners have encountered a "Plug-in Charging System Malfunction" message, which may take a day or two to resolve. The cost for diagnosing a check engine light issue is approximately $129, and it is recommended that owners address these problems promptly. While there are methods to reset the check engine light, it is advisable to first identify and fix the underlying issue to maintain the vehicle's optimal performance and safety.