Possible Causes

Possible causes are:

• Aftermarket EVAP hardware (i.e. fuel filler cap) not meeting required specifications.
• Canister vent solenoid stays partially open on closed command.
• Damaged, cross-threaded or loosely installed fuel filler cap.
• EVAP system component seals leaking such as EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control check valve tube assembly or fuel vapor vent valve assembly.
• Loose fuel vapor hose/tube connections to EVAP system components.
• Small holes in fuel vapor hoses/tubes.