Toyota Prius 2011, Owner'S Manual

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6-1. Specifications
PRIUS_U (OM47685U) DVD
Fuel information
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Fuel tank opening for unleaded gasoline
To help prevent incorrect fueling, your Toyota has a fuel tank opening that
only accommodates the special nozzle on unleaded fuel pumps.
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If your engine knocks
l Consult your Toyota dealer.
l You may occasionally notice light knocking for a short time while acceler-
ating or driving uphill. This is normal and there is no need for concern.
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Gasoline quality
In very few cases, driveability problems may be caused by the brand of gas-
oline you are using. If driveability problems persist, try changing the brand of
gasoline. If this does not correct the problem, consult your Toyota dealer.
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Gasoline quality standards
l Automotive manufacturers in the US, Europe and Japan have developed
a specification for fuel quality called World-Wide Fuel Charter (WWFC)
that is expected to be applied worldwide.
l
The WWFC consists of four categories that are based on required emis-
sion levels. In the US, category 4 has been adopted.
l The WWFC improves air quality by lowering emissions in vehicle fleets,
and customer satisfaction through better performance.
Your vehicle must use only unleaded gasoline.
Select octane rating 87 (Research Octane Number 91) or higher. Use
of unleaded gasoline with an octane rating lower than 87 may result
in engine knocking. Persistent knocking can lead to engine damage.
At minimum, the gasoline you use should meet the specifications
of ASTM D4814 in the U.S.A. and CGSB3.5-M93 in Canada.