DTC P0451: EVAP System Pressure Sensor Range/Performance Problem
- Perform test procedure. See TESTING PROCEDURE . If DTC P0451 is only DTC set, go to next step. If any other DTCs exist, diagnose and repair those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . Clear memory. See CLEARING DIAGNOSTIC TROUBLE CODES . On Forester, Legacy and Outback models, validate repair by performing appropriate drive cycle. See DRIVE CYCLES . On Impreza and Outback Sport, perform verification procedure. See VERIFICATION PROCEDURE .
- Turn ignition off and check installation of fuel filler cap. If fuel filler cap is tightened securely, go to next step. If fuel filler cap is not tightened securely, tighten fuel filler cap. Clear memory. See CLEARING DIAGNOSTIC TROUBLE CODES . On Forester, Legacy and Outback models, validate repair by performing appropriate drive cycle. See DRIVE CYCLES . On Impreza and Outback Sport, perform verification procedure. See VERIFICATION PROCEDURE .
- Check for any disconnected, clogged or leaking vacuum hoses and pipes between fuel tank pressure sensor and fuel tank. Also check for any disconnected, clogged or leaking ventilation hoses and pipes between fuel filler pipe and fuel tank. If damage is present, repair or replace any faulty hoses and pipes. If damage is not present, replace fuel tank pressure sensor. Clear memory. See CLEARING DIAGNOSTIC TROUBLE CODES . On Forester, Legacy and Outback models, validate repair by performing appropriate drive cycle. See DRIVE CYCLES . On Impreza and Outback Sport, perform verification procedure. See VERIFICATION PROCEDURE .