2004 Prius EV (Electric Vehicle) Button Installation Instructions

2004 Prius EV (Electric Vehicle) Button Installation Instructions

*Disclaimer: The modification below is undertaken at your own risk. It could result in damage to your vehicle. You could be injured doing the modification. It could easily void your warranty. It may reduce your gas mileage. It may shorten the life of your NiMH battery and lead to early replacement not covered by the Hybrid Warranty. It may irreversibly damage the HV ECU (Hybrid Computer) of your car and require expensive replacement. Neither the author, Evan Fusco, MD nor anyone distributing this document will be held responsible for injuries or damage or financial loss resulting from any of the modifications. If you choose to make these alterations to your vehicle you do so at your own risk and responsibility. The information here is provided for informational purposes only and it is not suggested or advised that you carry them out. You should not try this unless you are reasonably comfortable working with electronics. I provide no guarantee that the information contained here is accurate though I've tried to assure that it is.

These instructions allow you to take advantage of the built-in feature of what is commonly called "EV (electric vehicle) Mode" of your 2004+ Prius. In Japan and European versions of the Toyota Prius, the vehicle is sold with an EV Button pre-installed by Toyota. For some reason, in the North American version this button is left off (note: speculation focuses on possible EPA/NHTSB regulations that were unclear as to whether the option to use 2 different 'fuels' was legal. Also, it has been speculated that the decision came from Toyota, but no clear statement, at this writing, has come from Toyota. The EV button MAY become a dealer option or as a standard feature on future model year Priuses). However, the HV ECU is programmed for the EV button. Accessing this feature is a basically simple procedure. One simply needs to plug a wire into the proper plug on the ECU, attach that wire and a ground wire to a momentary switch and EV mode is available. Unfortunately, accessing the proper pin to plug the wire into the ECU plug, accessing the ECU and threading the wire and finding a ground are a bit tricky. These instructions are designed to take you step by step through the procedure.

Download 2004 Prius EV (Electric Vehicle) Button Installation Instructions

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