Technical Definition:

Evaporative Emission System Leak Detected (small leak)

Technical Description:

Possible Causes:

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal
Defective vent valve
Defective purge valve
Defective leak detection pump

Possible Symptoms:

• The only thing you will notice is the Malfunction Indicator Lamp (MIL) a.k.a.
• Check Engine Light will be illuminated.
• You likely won’t notice any drivability problems although sometimes a fuel odor may be noticed.

Evaporative Emission Control System Leak Detected Small Leak

Possible Solutions:

• Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
• Otherwise, replace the gas cap (we recommend an OEM not aftermarket part), or
• Inspect the EVAP system for cuts/holes in tubes/hoses

OBD-II Trouble Code Type:

Diagnostic Step:

• Using an advanced scan tool, perform an EVAP leak test
• Verify operation of the EVAP purge solenoid / valve
• Perform a smoke test to see where the leak is
• Generally there are vehicle and model specific procedures for proper diagnosis of this DTC.

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
– EVAP canister or fuel tank leaks
– EVAP system hose leaking
– Fuel tank leaking

Specific Makes:

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