P0440 — Evaporative Emission Control System Malfunction

P0440 is a generic EVAP system fault — your fuel vapor recovery system isn't sealing properly. Like P0455, the gas cap is the #1 culprit.

Cost range: $0–$500. Severity: low. Safe to drive? Yes, no drivability impact.

Most common causes of P0440

1. Loose or faulty gas cap — Tighten or replace. ($0–$25)
2. EVAP hose leak — Visual inspection of rubber lines. ($20–$150)
3. Bad purge valve — Common on older GM and Ford vehicles. ($80–$300)

Symptoms drivers report with P0440

• CEL only