P0454 — EVAP System Pressure Sensor/Switch A Circuit Intermittent

P0454: EVAP System Pressure Sensor/Switch A Circuit Intermittent — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

EVAP System Pressure Sensor/Switch A Circuit Intermittent. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Check-engine light, often without obvious running changes.
  • The pressure signal becomes intermittent; this differs from a proven intermittent physical vapor leak.

Possible causes

  • Loose sensor connector, oxidized terminals or intermittent wiring contact.
  • Failing EVAP/tank pressure sensor or unstable reference/ground connection.

What to check

  • Record P0454 and associated faults before clearing anything.
  • Inspect EVAP pressure-sensor wiring, connector locking and signs of moisture.
  • Watch pressure signal live data for dropouts under manufacturer-approved conditions.
  • Check supply, ground and signal continuity while avoiding damage to sealed wiring.
  • Repair the confirmed intermittent electrical defect and verify repeatability.

Also written as: P0454-00, P045400, PO454 (some scan tools add the fault-type byte, e.g. -00).