Toyota 2013 Prius Owner's Manual page 203

1-7. Refueling
Fuel types
■
Use unleaded gasoline. (Octane rating 87 [Research Octane Number 91] or
higher)
If the fuel filler door opener is inoperable
■
If the fuel filler door opener switch cannot be operated, contact your Toyota
dealer. In the event that urgent refueling is required, follow the procedure
below.
STEP 1
STEP 2 Remove the cap slowly. Take care to prevent fuel from spilling
out, as fuel tank pressure may not have been adequately
reduced.
STEP 3 Fill the fuel tank carefully and slowly. Use caution, as air being
discharged from inside the fuel tank may cause fuel to spray out
from the filler opening during refueling.
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PRIUS PHV_OM_OM47787U_(U)
Open the fuel filler door using the lever in
the luggage compartment.