You finished towing your boat or trailer with the Telluride and now the check engine light is on. P0455 indicates an EVAP system large leak—but the timing after towing often points to a simple cause rather than a real leak.
Why After Towing?
Towing creates conditions that can trigger EVAP codes:
- Fuel sloshes more during trailer maneuvers
- You likely filled up before the trip
- The gas cap may have been disturbed during prep
- Extra vibration can loosen connections
What P0455 Means
The P0455 code indicates a "Large Leak" in the Evaporative Emission Control System. This system captures fuel vapors and routes them to the engine. A "large leak" to the computer might be as simple as a loose gas cap.
The Simple Fix
- Pull over safely
- Remove the gas cap completely
- Inspect the rubber seal for damage or debris
- Reinstall until you hear 3+ clicks
- Drive normally for 50+ miles
- The light may turn off automatically
If the Light Doesn't Clear
If proper gas cap seating doesn't resolve it:
- Try a new gas cap - OEM recommended
- Inspect EVAP lines - Look for disconnected hoses
- Check vent valve - Located near fuel tank
- Professional diagnosis - Smoke test identifies actual leaks
Towing-Related Considerations
Heavy towing puts strain on multiple systems. While P0455 is likely unrelated to towing stress, use this as an opportunity to check:
- Transmission fluid level and condition
- Coolant level
- Brake fluid
- Overall vehicle condition
Repair Costs
- Gas cap: $15-$40
- EVAP line repair: $75-$250
- Vent valve: $100-$300
- Smoke test diagnosis: $75-$150