Automotive OBD-IILow Severity
P0455: Evaporative Emission Control System Leak Detected (Gross Leak)
Applies to: Universal OBD-II (Ford, Chevy, Honda, Nissan, Hyundai)
Safety & Usage Advisory
Can you still drive / use device? Yes. Completely safe to drive, but emissions test will fail.
Estimated Repair Cost
$15
$15 - $250 (DIY: $15 - $50)
Diagnostic Category
Automotive OBD-II
Universal OBD-II (Ford, Chevy, Honda, Nissan, Hyundai)
Fix Difficulty
Moderate DIY
~30-60 Mins Required
Common Symptoms
- Check Engine Light on
- Gas cap loose warning message on dashboard
- Slight fuel vapor odor near rear of vehicle
Root Causes
- Missing, loose, or cracked gas cap seal
- Faulty EVAP purge control solenoid
- Stuck open EVAP vent valve
- Cracked EVAP charcoal canister vapor hose
Step-by-Step Instructions to Fix P0455
1
Inspect and Tighten the Gas Cap
Remove gas cap, inspect rubber O-ring for cracks, tighten until it clicks 3 times.
Tools / Software Required: None
2
Replace Gas Cap with OEM Replacement
If the cap rubber is dried or cracked, replace with genuine OEM cap ($15).
Tools / Software Required: New OEM Gas Cap
3
Test EVAP Purge Solenoid Under Hood
Disconnect electrical plug and vacuum hose. Apply 12V; verify valve seals tight when unpowered.
Tools / Software Required: 12V Probe, Vacuum Pump
4
Inspect EVAP Canister Vent Valve Near Gas Tank
Check vent valve for road salt corrosion or spider nest clogs.
Tools / Software Required: Flashlight, Jack Stands
5
Smoke Test EVAP System
Pump mineral oil smoke into EVAP port to reveal any hairline cracked lines.
Tools / Software Required: EVAP Smoke Machine
How to Prevent P0455 in the Future
- Always tighten gas cap until it clicks 3 times after filling up.
P0455 Troubleshooting FAQs
The OBD-II EVAP monitor runs when fuel tank is between 1/4 and 3/4 full. It typically clears within 2-3 cold-start drive cycles.