- After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
- Small holes or cuts in fuel vapor hoses/tubes
- Canister vent solenoid stays partially open on closed command
- Damaged, cross-threaded or loosely installed fuel filler cap
- Loose fuel vapor hose/tube connections to EVAP system components
- EVAP system component seals leaking (EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve assembly)