It took me a little while to figure out *exactly*what the key sequence was to get the CTS-V fix to work, and for me the best method to get it to work was to hold down the "next track" button (right "seek" arrow) and then tap and release the second button from the bottom, then release the parking brake. Works every time without fail, where for me the "double tap" method didn't work every time.
I think what's basically happening is that you're getting the diagnostic screen for the nav unit, which probably stops it from listening to the data bus temporarily, but for some reason the DVD picture & sound has priority over the diag screen so you're not seeing it. If you do that same key sequence while you're NOT watching a DVD you get the diag screen which on my '04 CTS-V allows you to cold-start the GPS (not recommended - when I did that my car thought it was on Manhattan Beach in California and driving off into the ocean, and took a good 5-10 minutes to re-aquire a GPS fix). There's also some Nav system version information in there.
I think the best technical solution to this problem would be to create a filter that would read the messages on the data bus, and allow everything through except for whatever two messages tell the Nav system that you've released the parking brake and you're moving more than 3mph. I don't know if it's just my imagination or not, but it seems like the nav system allows you to enter destination addresses and stuff for a little while if you're moving very slowly. It could be that it allows entry under a certain mph (like 3mph or something) or it could also be that the vehicle speed is only broadcast on the data bus with a certain frequency and the message just hasn't gotten to every module yet...
Unless the Nav system is doing the "speed > 0" or "speed > 3mph" calculation internally based on the vehicle speed being available on the data bus, it should be possible to filter out the "parking brake release" and "vehicle moving" messages without crippling any other functionality of the Nav system, like the distance travelled functionality that allows the nav system to tell where you are even when you're in a tunnel and don't have a GPS signal.
-B
PS: I'm not a digital signal guy, so I would have no idea how to selectively filter out certain data bus messages, but it might be as easy as just having a couple of NAND gates and comparing the messages coming across the bus against some dip switches that represent the message you're trying to filter out.
Quote:
Originally Posted by Hockeydad  Here's what I posted a few pages ago....I have an 05 "V" and this works with no problem.
Thanks for the reply....I did some more searching and found out some more info about the process found at Reed's Place http://www.cadillacfaq.com/faq/answers/dvdmotion.html The key is to perform the button mash twice...the first time you will get the cold reset screen...that's O.K. it's supposed to do that...just do the button sequence again and the movie will still be playing...release the parking brake and viola...rolling DVD enjoyment. Some folks have stated that the headlamp switch can't be in the auto position but mine worked in both settings. |
Re: DVD Nav Override? (I wanna play movies!) 
