Possible Causes

Possible causes are:

• Blockages or kinks in EVAP canister tube or EVAP canister purge outlet tube (between fuel tank, EVAP canister purge valve and EVAP canister).
• Canister Vent (CV) solenoid stuck open (partially or fully).
• Contaminated fuel vapor elbow on EVAP canister.
• Damaged FTP sensor.
• EVAP canister purge valve stuck open.
• Fuel filler cap stuck closed (no vacuum relief).
• Plugged CV solenoid filter.
• Restricted EVAP canister.
• VREF circuit open (harness near FTP sensor, FTP sensor or PCM).