For safety, stepping on the brake before starting has always been highly recommended in all types of vehicles anyway. But in Prius, it is required. Because if you don’t, you’ll find that only the accessories will power-up. The hybrid system itself won’t start until you push the power button while also stepping on the brake at the same time. If you do make the mistake of not pressing the brake pedal far enough to the floor, a collection of warning the lights by the speedometer will come on. In that case, lift your foot off the brake. Wait a few seconds, and then press it again… only harder this time.
Wait a few more seconds, and then press the PARK button. That will reset the system. 12-Volt Jumping If the 12-volt auxiliary battery is ever drained completely, you can jump it similar to a traditional vehicle. With the Prius OFF (hybrid system & lights), connect the positive-cable to the jump-start terminal (within the black plastic fuse-box, under the Prius hood) then to the positive-terminal on the 12-volt battery of the supplying vehicle (as it is running). Next, connect the negative-cable to the negative-terminal on the 12-volt battery of the supplying vehicle. Then the other end of the negative-cable can be connected to an unpainted metal component under the hood; a very good place for this is the support attaching the engine & motor to the body of the vehicle in the front driver’s side corner under the Prius hood. At this point, start the hybrid system. When “READY” appears on the Prius speedometer cluster, you should then disconnect the cables following the opposite order they were connected. For safety information, greater detail, and illustrations, please refer to your Owner’s Manual. A very simple way to confirm you have a good electrical connection before attempting to start is to just turn on the ceiling light. If it illuminates brightly, you know that the supply coming from the donor vehicle is sufficient to successfully jump the Prius. If the light is dim, the connection is bad and you must fix it before proceeding.
Get pdf Toyota Prius Users Manual