Navigation lockout switch

The key is to insert a switch into the speed sensor wire into the NAVI unit.
The sensor wire signal tells the NAVI to gray out once the speed reach 5mph and above.
(same for Toyota/Lexus, etc.).
Every model is difference. You need to find the Wiring Manual of CX-9 and find
THAT WIRE. Once you know where it is, the rest is easy. However, the manual costs
$85. I am not even sure I DEFINITELY can find it in that manual.
 
I can sure that NAV lockout senses the vehicle's speed. I already check with my CX9. So it will be the same with Ford in thread above. Just need to find out VSS on back of NAV, or VSS wire connected to it.
 
The programming may not rely on the VSS; the GPS itself can tell its own speed and lock out based on its own speed. In that case the wire to put a switch on would be the GPS antenna. It seems like that's the wire that is switched on the youtube videos of Mazda's with the lockout removed, as the GPS is nonfunctional while the lockout is removed.
 
aciurczak said:
The programming may not rely on the VSS; the GPS itself can tell its own speed and lock out based on its own speed. In that case the wire to put a switch on would be the GPS antenna. It seems like that's the wire that is switched on the youtube videos of Mazda's with the lockout removed, as the GPS is nonfunctional while the lockout is removed.
Click to expand...

If the navi is grayed out when driving in a tunnel (no GPS signal) it is in fact controlled by the VSS (if not both the GPS signal and the VSS)
 
I am pretty sure it is controlled by the VSS (vehice speed sensor?).
On Prius, the guy created a kit to interrupt the sensor. See the link.
www.coastaletech.com
It is basically a switch to temporarily cut the speed sensor info into the NAVI unit
so that the gray-out does not occur. Our NAVI is also made by Denso, same as that on
Prius. I don't see why it can be different on CX-9.
You can try it at a parking lot. Drive very slowly. Once the speed goes above 5mph, the gray-out kicks in.
On Prius with digital speed display, it is very obvious. You can do this very very slowly.
GPS cannot determine speed at such slow movement. It has to be the VSS.
 
GPS can absolutely determine whether it is moving 5 mph or not; even the cheapo consumer ones have a repeatable resolution of 1 mph. That said, OMF's point is likely spot-on; this can be verified in some basement parking garage to confirm that the lockout enables/disables regardless of no GPS signal.
 
In a Prius which has digital display of speed, you can easily play with this gray-out by varying speed between 4 and 5mph.
When I said "slow movement", I didn't mean it by "accuracy". GPS measurement is of course accurate in measuring average speed, but it is NOT accurate in term of instant speed.
 
I guess it depends on what you mean by instant. Since it is calculating over time, it isn't instant. But the consumer grade stuff is calculating speed 5 times per second (0.2 seconds between readings), and displaying it once per second. Military grade GPS units can calculate speed 50 to 100 times per second. The "instant speed" representation on GPS alone would be easily fast enough to toggle the on/off behavior you describe in the Prius; but you're undoubtedly correct that it is currently done with the VSS.
 
The range of error in commercial GPS is about 10m = 30ft.
Even if it computes 100 times per sec, it means very little when you drive at 5mph. (5mph = 7.3ft per sec). Is your GPS accurate within 7ft? I doubt that. That is within military spec.

That said, speed data is readily available in auto electronics, why one needs to reply on GPS for such info?
Anyway, I am guessing you didn't read the link I provided.
www.coastaletech.com
See how this guy invented a device to split the VSS wire into NAVI unit to make gray out not happening. Did he temper with GPS? I don't think so. One Ford forum, there was also a guy who cut the wire and install a switch himself. And it works. No GPS involved.
 
GPS positional accuracy is significantly better with WAAS, it's more like 3 meters rather than 10. But that's not how most GPS devices calculate velocity anyway; velocity is calculated via the dopplar effect on the GPS carrier frequency; it is only augmented by the relative position change.

In other words, GPS units do not calculate speed simply by taking location reading of where they are, taking the next location, and calculating the delta. Using the range of absolute error (not relative error) to estimate the error range of velocity is not an accurate representation. The fact is current consumer (and commercial) GPS units are rated down to 0.1 mph accuracy.

I read the link you posted, and I'm glad it is getting easier to find products to allow full operation while in motion. You're making an assumption that all car navigation lockouts are engineered the same as the Ford unit. The assumption may in fact be correct.

I wish that all manufacturers were more like Honda/Acura, who don't put any motion lockout in their nav units. Once you hit the first "OK" message, they allow full operation no matter what. It's a shame that these workarounds are even necessary in other manufacturer's cars.
 
I remember scanning through the wiring diagrams for "VSS". Have not found it!

Unfortunately I don't have the wiring diagram book with me, but I do remember a cable connection between the navigation unit and the instrument cluster - my #1 bet for the VSS cable. I will pdf the diagrams for your review over the weekend.
Note: My manuals are for 2007 model year!
 
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