Section 42 (Engine Controls - Self-Diagnostics - 2.5L): Summary
WARNING: This page is about a different car, the 2003 Subaru Outback, 2003 Subaru Legacy, 2003 Subaru Impreza, 2003 Subaru Forester, and 2003 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.
If no hard fault codes are present, driveability symptoms exist or intermittent codes exist, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.