Engine Error
P0456
Evaporative Emission System Leak Detected (Very Small Leak)
Severity
Low
Symptoms
Check engine light, failed emissions
Common Causes
- Pin-hole leak in EVAP line
- Hairline crack in gas cap seal
- Vapor pressure sensor leak
- Failing vent valve gasket
How to Fix
- 1 Replace gas cap
- 2 Perform high-sensitivity smoke test
- 3 Replace vent valve
- 4 Inspect fuel filler neck
Estimated Repair Cost
USD
$30
–
$400
Gas cap: $30; Smoke test: $100 - $150