What are OBD-II Trouble Codes? OBD-II (On-Board Diagnostics) trouble codes are diagnostic codes that are generated by a vehicle’s computer system. These codes are designed to help mechanics and technicians identify and diagnose issues with a vehicle’s various systems and components. What is the Subaru OBD-II Trouble Code P0B26? The Subaru OBD-II Trouble Code P0B26…