EVAP System Large Leak Detected
What it means
The evaporative-emissions system has detected a large leak — most often a missing or loose fuel cap.
Symptoms
Check-engine light; possible fuel vapour smell.
Common causes
Missing/loose/faulty fuel cap, disconnected or cracked EVAP hose, faulty vent valve.
Recommended action
Tighten or replace the fuel cap first; if it persists, smoke-test the EVAP system for leaks.
Related codes
FAQ — P0455
What does code P0455 mean?
EVAP System Large Leak Detected. The evaporative-emissions system has detected a large leak — most often a missing or loose fuel cap.
What are the symptoms of P0455?
Check-engine light; possible fuel vapour smell.
What causes P0455?
Missing/loose/faulty fuel cap, disconnected or cracked EVAP hose, faulty vent valve.
What should I do about P0455?
Tighten or replace the fuel cap first; if it persists, smoke-test the EVAP system for leaks.
General reference based on the SAE J2012 standard. Exact causes for your vehicle may differ — when in doubt, consult a workshop.
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