Hey guys,

After looking at the NAV hack and comparing it to the car's schematic, I found that the hack is bypassing the NAV's vehicle speed signal input. This signal is used by the NAV system for dead-reconing navigation. This is necessary when the GPS receiver does not have a good satelite lock and depends on the speed signal to know that the car is moving and estimate its new position until a new satelite fix is made.

With this signal now unavailable, the system is unaware of vehicle motion during times when the GPS signal is gone. So, it will miss your turn (bad luck it was when the satelites were not in range) and then mysteriously know when you got home (clear view of the sky).

It's the connection to the speed signal that differentiates an installed GPS from a dash-mounted one.

Just thought you would like to know.

 

Very interesting... I have not done the nav hack on my IS, too scared to be cutting wires and pulling things apart, but very good info.

 

Hmmm...yes, this makes sense. In fact, I think I had it happen to me last night for a second...I thought I had the "jumpy nav" problem, but then realized it was a one-off. Did not happen again.

Anyway, for those that have already done it (i.e. me) and those who are considering doing the hack, I would not hesitate to say that it is few and far between if this ever becomes an issue for you. The one experience I had last night corrected itself in a matter of seconds, and I would never--NEVER--trade the hacked nav for a few seconds of Nav instability once in a blue moon.

So, what I'm saying is that it really is a non-issue...that is, unless you live in an area where you have to always depend on the satellites...

 

i mentioned about this long long time ago when the 2is came out, saying that you have to put a switch on the speed signal, so you can shut it off and adjust the settings (put in new addresses and so) when the car is moving, but you have to "connect" back the speed signal after you do that for the nav to operate correctly. no one believed me....

i guess here's the proof....

just run that speed signal through a switch and put the switch somewhere close to you and passenger

 

I recently did my hack, and I live at a condo w/ underground parking. I have no problem w/ my nav sensing the "movement" of my car when it is underground (2 level underground). I'm not sure what i did differently but my NAV still knows when my car is moving BECAUSE I STILL have to do the "NAV OVERRIDE" to input address when i'm moving. So I believe the plug J50 (PINK WIRE) is a speed sensor for the telephone / audio side of things" WHERE the WHITE/SILVER wire that is the NAV speed sensing wire. Thats you u connect PINK (from car) to white/silver (P1 adaptor). I hope this help!

 

Incorrect,
You must not have read on about the NAV hack, although you do in fact clip the pink wire from the "multi display" you DO reconnect the speed signal to the white, silver banded wire BACK INTO the NAV computer so that it does in fact have the dead reckoning available to it, so no there is no problem when you have a diminished GPS signal

 

The reconnect (white wire) feeds the stereo for speed-sensitve volume. I could be wrong.

 

I think you are. According to what I've read, reconnecting that wire causes the nav display updates to become much smoother. If anyone with the nav hack has seen their progress on the map as they drive through a tunnel, they can answer the question for certain.

 

My thought's are why would you need to use the nav in an area you live? I think it would be more for use in an area or cities you are not familiar with and then the issue of cityscape tall buildings etc would force the system to use the speed to calculate location. Also what about bad weather conditions?

 

you would be surprise how well nav can perform in densely populated city building, i would suspect you would have to get something like nyc or in the really thick parts of chicago to experience problems. my other nav worked fine all the way up and down michigan ave and nowhere in downtown minneapolis did i have a problem. same goes with weather. we used to get blizzards in minnesota (not anymore) and nav never had a problem.

 

Hmmm...maybe I was wrong then, as far as what happened to me...anyone in LA experience a glitch when going from 101 South to 60E? I went the same way today and had the exact same experience as last night. It was short, but I noticed it was at exactly the same place. Right before the 60E exit, my Nav says I'm one street south and parallel to the 101 and then a few seconds later jumps back to being on the 101. I've never seen it happen anywhere else.

Again, it's really a non-issue for me, but I was just trying to determine if it's the system overall, or a result of the hack...

 

Well maybe I wasn't clear in my post. I didn't mean near in terms of being right around your house but moreso frequenting places where there might be a lot of construction, unpaved roads and other undocumented areas like that. I guess you can't really determine if you will always be in this type of environment, but it's probably more noticeable if you frequent a place like this (e.g. a place near your home, work, or shopping area)...

That said, even though I knew where my home was, when I bought my Acura MDX a few years ago, the nav didn't acknowledge my neighborhood since it was relatively new. It was annoying...

 

I have had my nav hacked since a week after I got my car in March.

Here I am 10,000 miles later (computer tech/consultant) and I have never had a problem with the navigation.

Follow the instructions very carefully. If you have installed a car stereo before then this "should" be a cake walk.

 

The signal is bypassed from the multi-display only. When the NAV Hack is performed, you are connecting the vehicle speed sensor directly to the NAV unit (the unit housing the NAV DVD).

I have no problems with jumpy NAV, and I have never missed a turn because of it. (I am running the navigation hack).

-Brian

 

I do not know if that is the reason or not, but my Nav shows the car positions off from the road.
What I mean is positions of car is running along next to road instead of on top of the road.
It starts at begaining of drive off and lasts from a few seconds to 15 seconds or so. Then everything is O.K.

I can deal with this, if it does not get any worse. It will bother me greatly if it lasts more than a few minutes but a few seconds, I can deal with it.