Refer to DTC P0451 EVAP. EMISSION SYSTEM-PRESSURE SENSOR RANGE / PERFORMANCE , DTC P0452 EVAP. EMISSION SYSTEM-PRESSURE SENSOR LOW INPUT , DTC P0453 EVAP. EMISSION SYSTEM-PRESSURE SENSOR HIGH INPUT and DTC P0454 EVAP. EMISSION SYSTEM-PRESSURE SENSOR INTERMITTENT troubleshooting procedures.