P0455 Toyota Highlander
EVAP System Leak Detected (Gross Leak) · Powertrain Code · Medium · Repair: Easy
What is P0455?
A large leak has been detected in the EVAP system. Check gas cap first — if secure, look for disconnected or cracked EVAP hoses, a stuck-open purge valve, or a leaking charcoal canister.
When the Toyota Highlander triggers code P0455 (evap system leak detected (gross leak)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Toyota Highlander.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Toyota Highlander.
Common Causes on Toyota Highlander
- Gas cap missing or severely damaged
- Charcoal canister housing cracked from heat and age
- EVAP VSV valve stuck open
- Large EVAP vapor line disconnect at fuel tank
- Fuel tank seal failure at pump assembly
Symptoms
- Check engine light illuminated
- Noticeable fuel smell near vehicle
- Gas cap warning light on dashboard
- Failed emissions test
- Fuel economy noticeably decreased
Notes for Toyota Highlander
RAV4 and Highlander charcoal canisters are prone to cracking, especially in hot climates. This is the most common cause of P0455 on Toyota SUVs.