P0456: Evaporative Emission System Leak Detected (Very Small Leak)
The ECM detects a micro-leak equivalent to a pinhole of just 0.020 inch (0.5 mm) in the sealed fuel vapor system.
Driveability & Safety Advisory
Safe to drive. No performance impact.
Official Manufacturer TSB Advisories
Factory Condition: Natural Vacuum Leak Detection (ESIM / NVLD) switch diaphragm stiffens in cold weather.
Physical Component Location & Service Access
EVAP canister switch on fuel tank or canister.
Electrical Specifications & Live PID Benchmarks
Scan Tool Live Data Targets
Digital Multimeter (DMM) Specs
Documented Model-Specific Case Studies
Root Cause: Faulty ESIM switch.
Verified Fix: Replace ESIM detector switch.
Technician Inspection & Testing Workflow
Clean gas cap rubber seal with clean cloth.
Smoke test system with 0.020-inch test gauge.
Inspect ESIM switch.
Recommended Diagnostic Tools & Verified Parts
BlueDriver Bluetooth Pro OBDII Scan Tool
Wireless sensor telemetry & enhanced diagnostics (Engine, ABS, Airbag). Delivers verified vehicle repair reports.
Autel AutoLink AL519 / AL319 OBD2 Scanner
Color screen standalone scanner. One-click I/M emissions readiness status, freeze-frame data, live DTC reset.
Stant / Motorad Direct-Fit Replacement Fuel Gas Cap
OEM grade replacement fuel cap with fresh Viton rubber seal. Resolves small and gross EVAP leak codes caused by cracked seals.
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Cost Breakdown
Tools & Parts Matrix
Diagnostic Questions & Answers
How small is a P0456 leak?
0.020 inches—about the thickness of a sewing pin!