Diagnosing Fuel Fill Problems

Diagnostic Chart:

Symptoms for a blocked inlet path will include:
^ Inability to dispense fuel at anything above "trickle" rate, if that. Fuel evident at fill head.
^ Nozzle will shut-off virtually immediately, since no volume of fuel can be dispensed.
^ Suspect a stuck inlet check valve. Check for operation with siphon hose.

Symptoms for a blocked/restricted vent path include:
^ Pre-mature shut-offs of fill nozzle at medium to high flow rates.
^ Nozzle will shut-off after dispensing only 0.76-0.14 L (0.2 - 0.3 gallons) (may be less with higher temperatures and/or higher RVP fuels). After a few second wait, this process can be repeated.

1. Connect Scan tool and check for DTC P0446.
2. Verify vent path:
^ Ignition On, Engine Off.
^ Using Scan tool, monitor FUEL TANK PRESS SENSOR.
^ Normal fuel tank pressure sensor signal voltage with no pressure or vacuum should read between 2.3 - 2.8 volts.
^ Check vent path from EVAP vent solenoid backwards to isolate problem component (vent solenoid, vent pipe/hose, canister, FLVV (fill limit vent valve), etc.).