Technical Definition:

Evaporative Emission System Leak Detected (very small leak)

Trouble Code: P0456
Address: 0x0456
System: Powertrain
Technical Description:

The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned.

Possible Causes:
  • A small leak in any of the EVAP hoses or fuel tank hoses
  • A small leak in the purge valve or vent valve
  • The EVAP Canister may be leaking

Possible Symptoms:

EVAP Control System Leak Detected Very Small Leak

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Missing or loose fuel cap
– Incorrect fuel filler cap used
– Fuel filler cap remains open or fails to close
– Foreign matter caught in fuel filler cap
– Evaporative Emission (EVAP) canister or fuel tank leaks
– Evaporative Emission (EVAP) system hose leaking
– Fuel tank leaking

Specific Makes:

– Possible a noticeable fuel odor caused by the release of fuel vapors

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