2009 Toyota Prius Owners Manual - Page 495

OM47614U_PRIUS_U.book Page 470 Monday, January 11, 2010 11:02 AM 6 -1 . Spe c ific a t ions Fue l infor m at ion 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. n 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. n If your engine knocks l Consult your Toyota dealer. l You may occasionally notice light knocking for a short time while accelerating or driving uphill. This is normal and there is no need for concern. n Gasoline quality In very few cases, driveability problems may be caused by the brand of gasoline you are using. If driveability problems persist, try changing the brand of gasoline. If this does not correct the problem, consult your Toyota dealer. n 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 emission 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. n Toyota recommends the use of gasoline containing detergent additives l Toyota recommends the use of gasoline that contains detergent additives to avoid build-up of engine deposits. l All gasoline sold in the US contains detergent additives to clean and/or keep clean intake systems. 470 PRIUS_U_(OM47614U)