Navigation Input Override (Speed Sensor Bypass)

Has anyone tried switching 12V to the speed pulse input on the stereo to bypass the lockout?

From what I've gathered from previous posts:

1) The full nav features work when the vehicle is stopped.
2) When the vehicle is stopped, 12 V is input into the stereo (0 Hz pulse)

This would be a much simpler solution than the 555 timer circuit. All you need is a switch, a 7812 voltage regulator, and 2 capacitors to smooth the signal from the 7812. The nav unit should see the vehicle as sitting still.

 

Sorry ECNiz, that's not quite correct. When stopped, there is no 12V signal input into the ECU. The ECU/NAV is internally "pulled up" to 12V, and when moving, the "speed" signal from the combination meter to the ECU/NAV pulls it to ground 4 times per wheel revolution.

Now, what would happen if you grounded it, and left it at ground? I don't know the answer to that........

 

If you do ground it, do it through a resistor. Start with a high resistance and work down until the voltage reaches a logic low level.

Tom

 

I gave this a try. When stopped and the SPD signal is connected, the level is at GND. When the signal is removed, an interesting thing happens. The nav input pin goes to ~5V. This doesn't seem to match the diagram in the repair manual, which shows the NAV input being pulled up to ACC (12V). This can be explained if there is some voltage division or conversion going on from NAV circuits not shown.

In any event, I disconnected the SPD signal and tried gradually bringing this input from 5V to ground. It basically responds the same way as if the SPD signal is cut entirely. It will unlock for 30 seconds, but then finally seems to realize that the GPS and dead reckoning are way too far off, and locks out for good, until the SPD signal is restored.

When the SPD line is reconnected, I verified again that the voltage pulse was 0-12V. So the combination meter is providing a full 12V pulse to this circuit, just as hawkmoon and I have implemented.

I did finish my installation of this mod as well. I was originally going to design an option to use one timer to only provide the "substitute" pulses for a short period of time - but the circuit was getting too complex (for what it was worth to me), and so I did the simpler circuit, basically the same as hawkmoon's. One difference was that I ran the pulsed output to the switch's LED (through a 1K resistor), so that the switch LED flashes at the same rate as the substitute pulse, and to serve as a reminder that the circuit was still connected and active. The switch I used came from a company in Milwaukee, WI, Del City:

Illuminated Paddle Toggles

It required a fair amount of Dremel-cutting of the "blank" for the "Parking assist" switch location (below the Power button) and also cutting the edges of the switch retaining nut to make it fit - but it worked and looks good.

My circuit is attached. Usual disclaimer applies. Not recommending this mod - just documenting what I have done.

Update: Added a 0.1 uF capacitor between Pin 8 (Vcc) of the 555 timer and ground. This cleaned up the noise before the positive edge of the square wave. Updated schematic attached.

 

Well I volunteered to be a 2010 Prius test vehicle for the Prestegious Society. Installed it today and it works great, kit is nice and relatively easy to install.

 

Sweet! Did they mention if/when they'll begin selling the Prius model? What features does it open up? All touch input while moving? Does it throw off the dead reckoning function of the GPS? So many questions... tell us more, please!

 

Tell us about the installation. What is required to instal the kit? Did you take any pictures?
Does it get rid of the I Agree screen?

 

You can get to everything like you were parked. The GPS doesn't get any input when it is on but the GPS seems to get it's position back almost instantaneously when you turn it off. It will time out after 5 minutes if you don't turn it off or enable it again. Don't know when they are planning to start sales but I will ask.

 

This is Mark's response to when it will be for sale.

"The module will be available to ship on Monday. We are working right now to update our website now so our potential client can order the module this weekend. "

Mark has been very helpful and responsive to my questions.

 

Doesn't get rid of the I Agree screen. I took pictures but they are for their instructions so I can't post them w/o their permission. The install requires you to get to the back of the Nav unit (take out the piece around the shifter, take out the piece with the cup holder, take out the piece with the start button, take out the trim around the Nav unit, 4 10MM bolts to take out the nav unit). Harness goes between 3 connectors on the back of the Nav Unit, find a place to mount the small electronics box (put mine on a shelf right behind the Nav Unit with supplied double sticky tape, and find a place for the switch (put mine on the ledge right below the steering wheel with supplied double sticky tape).

 

Mark just wrote me that: "we are putting the Prius module on the introductory sale of $250 plus $15 shipping (regular price is $299.49)
"

 

Those who are electronic savvy can do this by themselves.
Search the web for "corvette navigation override". There was a guy who published a cicrcuit diagram that sits between the violet wire (speed sensor) input to the MFD. The way it works is basically the same for most vehicles and models.
The speed sensor input are a train of pulses (certain voltage and frequency). His circuit diagram uses a variable resistor to tune the frequency of pulses (which corresponds to 'speed'). Once the speed is interpreted as "below 5mph", the NAVI lock-out is released.
Grounding it out will confuse the NFD and it will take a while to get back to normal (said to be 1 minute range). At 0mph, there are still pulses at much lower frequency.
The circuit basically centers around a IC 555 Timer with a couple of resistors and capacitors. It is a simply 1 afternoon project if you are up to it.
Just FYI.

 

The Prestigious Society web site is now accepting orders for the 2010 Prius over-ride module. Paypal payment.

Just ordered it...

 

You don't even need to search that far. There are two circuits like this posted in this thread.

The Prestigious Society's device is easier to install, I'm sure, since it simply goes inline with the existing connectors. But if you're interested in a relatively simple do-it-yourself electronics project, this thread contains all the info you need.

 

Anyone know if the Prestigious Society bypass for the Prius allows for DVD playback?

 

From their website:

"The DVD/Video override feature built into this override module is designed to enable full video playback for your passengers. If your vehicle is equipped with Rear Seat Entertainment System (RSES) option, the DVD/Video override will unlock the video on the navigation screen while the vehicle is in motion. If your vehicle is not equipped with factory RSES, the override module is compatible with many popular 3rd party video inputs which will enable video playback via the navigation screen."

 

I'm tempted, but I'm also tempted by the Vais SoundLinQ2 (SL2Vu). I know they aren't directly related. The PS brochure says their product is compatible with other 3rd party add-on products. I was thinking their product would not be affected by future upgrades to the Nav, but their brochure includes a warning that it could be.

 

You can email them to find out. I don't think the software update will affect anything, at least for my Lexus. I had their kit installed on my LS460L and later on upgraded to 8.1 to get rid of the I Agree. Everything still works fine after that. I think its just a precaution language.

 

placed my order. hoping for a simple plug and play. thanks for the info.