P0456: Evaporative Emission Control System Leak Detected (Very Small Leak)
19 vehicles · 12 makes
P0456 is an OBD-II diagnostic trouble code meaning “Evaporative Emission Control System Leak Detected (Very Small Leak).” A very small leak detected in the EVAP system. The smallest detectable leak, often intermittent. This code appears across 19 vehicle models from 12 manufacturers.
Common Causes
Diagnostic Tools
To diagnose P0456, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (19)
Canister Purge Valve Failure Causing Rough Idle and Stalling
EVAP Purge Valve Stuck Open (Hard Start After Refueling)
Canister Purge Valve Failure Causing Rough Idle and Hard Start
Fuel Filler Neck and Strap Corrosion Causing Fuel Leaks or Tank Movement
EVAP Canister Purge Valve Failure
Fuel Tank Cracking and Fuel Vapor/Fuel Leak at Tank Seam or EVAP Area
FAQ
What does P0456 mean?
P0456 stands for "Evaporative Emission Control System Leak Detected (Very Small Leak)." A very small leak detected in the EVAP system. The smallest detectable leak, often intermittent.
What are the most common causes of P0456?
The most common causes of P0456 are: Slightly loose gas cap, Hairline crack in EVAP hose, Minor gas cap seal wear, EVAP canister micro-crack, Temperature-related seal shrinkage. The specific cause varies by vehicle.
How much does it cost to fix P0456?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0456?
Au7o has documented P0456 across 19 vehicle models from 12 manufacturers: Chevrolet, Chrysler, Dodge, Ford, Hyundai, Infiniti, Kia, MINI, Mazda, Nissan, Subaru, Toyota.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.