STS navigation

[nukeduster]

Hey everyone,

Just got posed an interesting question from a buddy of mine who wants to modify his '05 STS. He wants to be able to watch movies on his factory nav system while the vehicle is in motion.. does anyone know of a way to modify it in order to be able to do this?

Any input would be appreciated.

[Richbro]

No one has posted the answer to this question yet and there have been many people ask. You might do a search on "motion" or "disable nav" and read to your heart's desire ... and ... if you figure it out, let a few thousand of us know.

[jgrade]

This may be a shot in the dark, but by accident I discovered the answer to the NAV question in a GMC Envoy. The system is slightly different and have I have not cracked the dash on the STS yet to compare so read with for info only.

On the Envoy system there is a brown (I think, it's been a while) wire in the large bundle that on first blush looks like a 12v ignition sense. Thinking that this was the wire I was looking for, while installing an aftermarket DVD, I tapped it. Well, the kids were mad when I put the car into gear, because the DVD would turn off. It turns out that the wire is connected to the gear shifter (read: easy to bypass, not a complicated sensor like the speed indicator for auto volume) and is 12V when in park or neutral??, but ground when in gear. SO I cut this wire and connected it to the ignition sense and the blacked out NAV functions are always accessible when driving.

Since the system is Bose( I know not the NAV but considered Bose), it may use the speed sense to determine the state of the programming; not good news but not the end of the world. In that case, some PIC programming would come in handy to reproduce the digital signal. Again I am assuming that the Envoy and Caddy systems are similar. I intend to find out when the weather gets better.

[radrims]

I'm waiting for someone to try this. They're both Denso units, could be similar.

http://www.rocoto.com/siennamods/dvd_mod.html
http://www.rocoto.com/siennamods/nav_mod.html

[czjlcp]

I am workng on this now if I find out anything I will post it. Just got my STS last night and I work for GM at the tech center looking thru the connector end views now give me a day or 2 and I will find it.

[czjlcp]

you can't do it unless you can reprogram it. It is not a wire it is a program. Once the car is out of park it sends a message to the BCM saying it is out of park than water marks what programs get turned on and what programs get turned off. If you just clip that wire it will send a error message and nothing will work. I talked to the release engineer now I am going to talk to the programer.

[dunroven]

STS owner here say's, "here here." Keep the passion for solution!
-john

[MT Vette]

Originally Posted by czjlcp

I talked to the release engineer now I am going to talk to the programer.

go czjlcp go
go czjlcp go
go czjlcp go

[throttlezone]

I dont care about watching DVDs but it would be nice to use the 80% of the NAV and Bluetooth buttons that are disabled while in motion. There has to be some way to overide this!

[jgrade]

czjlcp: Which wire is it? I want to trace the wire with a scope and see whats happening. It's all a matter of hijacking the signal and repeating the "park" command. Easier said then done at this point, granted, but not impossible.

[Richbro]

Originally Posted by jgrade

czjlcp: Which wire is it? I want to trace the wire with a scope and see whats happening. It's all a matter of hijacking the signal and repeating the "park" command. Easier said then done at this point, granted, but not impossible.

It might not just be a matter of hijacking the signal and repeating the "park" command. There are many ways to protect systems ... like counting the number of commands, looping through multiple times with different paths, heck, the software/firmware could easily be on board embedded in a chip, etc. which, by the way, sounds like czjlcp was indicating earlier.

[jgrade]

Maybe BUT we are not talking DOA encryption for black level information. I know from the Envoy that the speed sense wire is sent from the Bose processor and has a few short "words" to tell the head unit what seed the car is traveling. As long as those words are formed and spaced correctly with the appropriate headers, then everyone is happy.

I'm not sure why the embedding of the software/firmware on a chip makes any difference. The head unit still needs to be told that the car is in motion, the location of the firmware is not important, only where the signal comes from and what it looks like.

Another thing to consider is that the features that are blanked while the car is in motion become usable when the car is in gear but not moving. This tells me that the speed sense may be responsible for this happening or it is tied to the GPS which would be VERY bad news. I don’t think the later is true since the feature dim even when the car is going 1mph, too small to be registered by GPS. More likely it comes from the speed sense (which the GPS also uses when it gets lost) which is just another sensor that can be hijacked,

Of course this is all theoretical until I have time to crack the dash.

[Richbro]

Hey, wish you good luck - I'll be one of those asking you how you did it if you succeed.

We all know the software boys do things just for the heck of it sometimes - and, if there's liability concern of any magnitude.

[jgrade]

Interesting note: The menus grey out when the car (at least mine) is traveling >=6mph. Anything less, the menus and buttons are usable. Further evidense that this is tied to the speed sense.
As always, changing the programming would be the easiest route, but accessing the programming to upload new content would be nearly impossible.
Anyone have a guide for removing the dash? I hate to experiment with a new car.

If I am successful I will post a guide.

[Swine]

The 1791 code doesn't work?