I am annoyed at the pedestrian alert noise maker on my 2022 Prius. Especially when it's in reverse. It sounds like a flywheel is grinding against a clutch, and a couple of people have stopped me to let me know that something is "wrong" with my Prius. I understand federal law frowns upon tampering with this thing (then again, who here among is truly innocent), but it has got to go. I considered ripping the speaker out and putting in a resistor in its place to prevent the ECU from throwing any engine codes, but I thought a better compromise would be to somehow pipe my own audio, something more palatable to the speakers. With that in mind, has anyone attempted such a thing or are there any guides on even going about this?
From what I understand the noisemaker is just a small tweeter/speaker right? I'd rather keep the mods I do reversible just in case. I don't know how exactly they're generating the distinct sounds though (playing a pre-recorded sound, real-time synthesis, or using some sort of electro-mechanial effect to create the sound) I wonder if I could splice in an Arduino and have it play back a sound file whenever the reverse switch is on.
From looking at mine, I believe the annoying UFO sound is hard-wired in the speaker. There's only 2 wires on the connection which seems to mean it's just to turn it off/on. I had a resistor to try but, instead, just insulated it very well with foamy pipe insulation...that way I can just remove it if I ever had a need to trading in the car. (If our Toyota/Lexus is 6-years old or newer, Toyota will "certify" it for resale but only if no major accidents or modifications have been made.)
A speaker also needs only two wires. As the Repair Manual (more info) explains, “A waveform synchronized with the sound is output” to the speaker by the vehicle approaching speaker controller or (on 2016–2019 models) by the hybrid vehicle control ECU. There is also an illustration of the waveform (1 V/div., 500 ms/div.):
Thanks for this info! So it looks like Vehicle Approaching Controller is outputting an analog signal to the speaker. I guess I could splice in an Ardunio downstream of the controller (or find some other means to sense when I'm in reverse or < 20 MPH) and pipe my own sound instead.
But for FMVSS No. 141, 49 U.S.C. §§ 30112 and 30122, and the amount of tedious disassembly required to get to it (the Repair Manual says you have to remove the rear seats, among other parts), I’d expect a thriving aftermarket in vehicle approaching speaker controllers with customizable sounds.
Mine has a button. But AFAIK the JDM models are the only ones to have the button - all other models do not. Australian New - JDM - Note the extra button. Wonder if it would be possible to use the same method to retrofit the mute button on cars that don't come with one.
depends on how you describe easy, but there are threads on how to do it. unfortunately, if you disconnect a wire, you get a trouble code. you have to install a diode, iirc.
On early fourth-generation Prius cars built for sale in Japan (and perhaps also Taiwan), the vehicle approaching speaker switch (also called the approach notification pause switch, 接近通報一時停止スイッチ) is wired between the ECU-IG1 NO.4 circuit and terminal F3-22 (SW) on the hybrid vehicle control ECU, such that 12 volts is applied at the ECU when the switch is pressed. I don’t know how the ECU software on versions of the car built without the switch would respond to voltage applied at that terminal. Later Japanese models don’t have the switch, by the way. The pause feature was allowed under the 2010 guidelines (page in Japanese; see attachment 3, paragraph I.2.(2)) but is prohibited by current Japanese regulations (PDF, in Japanese), in line with UNECE Regulation No. 138, Revision 1 (PDF), paragraph 6.2.6. The “make inoperative” provision, 49 U.S.C. § 30122, applies only to a “manufacturer, distributor, dealer, rental company, or motor vehicle repair business,” not to owners working on their own cars. See also National Traffic and Motor Vehicle Safety Act of 1966 As Amended: Legislative History, Volume IV (PDF), pages 489–490, quoting portions of the House debate (120 Cong. Rec. 27,807–27,808 (1974) (PDF)) on the Motor Vehicle and Schoolbus Safety Amendments of 1974 (PDF), Pub. L. 93-492, § 103, 88 Stat. 1470, 1477 (1974). This doesn’t provide any relief from state laws or civil liability, however. A resistor, in place of the speaker, not a diode.
Did you figure out where the speaker is located and how to remove it without causing a warning light on the front dash?
