Fuel Filler Cap: Testing and Inspection

Fuel filler cap includes vacuum valve and pressure valve.
In case any high vacuum and any high pressure happen in tank, each valve works to adjust the pressure to prevent the tank from being damaged.

Inspection
Check the seal ring in the filler cap for presence of any abnormality and for seal condition.
Replace the filler cap, if abnormal.

CAUTION: The fuel filler cap valves have characteristics. A defective valve, no valve at all or a valve with the wrong characteristics will do a lot of harm to engine operating characteristics; be sure to use the same fuel filler cap as installed in this vehicle.