Help Needed In Modifying The Sat/nav System

[lexussport]

Hi,

I am trying to modify the Sat/Nav (DVD) sytem in my GS 430 to enable me to input destinations whilst moving. This is so my son can do this whilst I am driving, so I can keep my eyes on the road and all that.

I had heard that others had done this, but with no real detail on how to do it. So Chris (Sporties son) and I set about the task yesterday. Our first problem was identifying the speed input to the Nav ECU. This was fun, picture this:- boot open, Chris lying in boot with a multi meter measuring the voltages going into the ECU in the boot. All this whilst I drove the car up and down the close, shouting instructions through the window to him.

He was a good lad telling me what the meter said, but it's not the same as seeing it myself. So plan "B" jack the rear of the car up with one wheel of the ground. Lots of blocks under wheels to stop the car moving. Selecting drive, letting one rear wheel revolve whilst lying in the boot measuring the inputs to the ECU. Yessss found the input!!!!!!!!!!!.

So we then installed an electronic timer (Maplin IC 555 kit) into the speed senser wire input to the ECU and off down the road to test it out.

We start the timer which disconnects the speed senser from the Nav ECU (computer) for a preset time (initialy set to approx 2mts) and so the computer thinks the car has stopped and this enables you to enter the destination whilst driving. However the computer must be quite clever as after approx 22 seconds the buttons grey out and the satellites take over the navigation. Even though there is no input from the wheel speed sensers.

We then have to wait 10 seconds before reactivating the timer, which then gives us another 22 seconds to finish the inputting before the computer takes over etc etc.

So the problem now is how to make the time longer before the ECU works out that there is no input from the wheel speed sensers and get the satellites to take over?

One thought is to disconnect the GPS aerial at the same time as the speed senser, so that the system has no idea were it is until the input is finished and then we reconnecting both?

But I would prefer not to cut the aerial wire unless we have to as i want it to be easy to install and remove.

I would be grateful of any help or ideas you may have in solving this problem?

Once solved, easy step by step instructions will be posted for others to benefit.

Sportie. :D

[Mike246]

I agree that it is really annoying that manual inputs are supressed while on the move.

My theory is that this is initiated by boot settings on the disk itself. I recently bought a new disk (CD-ROM version) and I am now permitted to switch to trip computer while driving.

My other theory is that deactivation of the route setting can be over-riden through the SatNav's maintenance mode. I'll follow this through with my dealer's Service Manager but how about a petition from like-minded Club members to Lexus GB to sort this out?

[Michaelsb]

Hi Guy's

I currently have sat/nav and TV as a factory fit in my family car and that allows switching between trip computer - TV - and sat/nav and imputs while on the move, I am picking up a new SC on March 1st and if that will not allow input on the move I will gladly contact Lexus jointly with you. My wife often enters new info while I am driving and it would seem daft to have to stop the car to do so.

Good luck sorting it out

Regards

[agalbraith]

I was under the impression that this could be altered through the maintenance menu too... but as to where to start....

I'd certainly add my voice to a petition to Lexus. I can see that they may potentially want us to sign a waiver (such that we can't sue them should we have an accident whilst adjusting the satnav in motion)

A

[L3X JG]

there is a problem with what you are trying to do

The first major problem is that to calculate the route the car should be stationary because it works our the route from that point, The other is that if you disconect the GPS ant it may take 20min + to pick the sats back up the system will not work very accuraty with the speed wire disconected at high speed it will lose pace with the car and you will be approching turns before the nav unit.

the only way to do it would be to diconect the GPS ant but this is an area that i would not touch and there aint many areas on a car that i will not touch

If it were me i would put a latch switch on the speed wire and just use that to break the speed wire so when it picks up on the sats you switch the speed wire back on let it regain control then break it again it a lot of hass i know but the only simple way.

sorry to put a downer on the topic

[Geoffers]

I don't know much about the Satnav side of things on the lexus yet (I will next week when I get mine!), but I believe that it is a pulsed negative sig. when the car is moving. Over roughly 5 miles per hour and it disables the buttons.

Have a look at the pulse when you are doing less than the cut off speed. (For talking sake, say, 2 per second) and using your 555, set it in astable mode and pulse the line with roughly the same timing as if you were doing less than 5 miles per hour. (Leaving the original speed sig lead disconnected). I don't know if it uses the speed sig to override to sat. pos sig difference when you are moving. Providing it does, then there should be no reason why this doesn't work.

Might be talking out of my bum here because I've not tested anything and only working on bits I've picked up on, but it maybe worth looking at.

L3x jg has a good point - speed, distance, etc is a big factor on the accuracy. It will be reliant only on the Sats for positioning. If you used this method, put a switch on to change over between the two methods.

[TonyGoose]

My other theory is that deactivation of the route setting can be over-riden through the SatNav's maintenance mode. I'll follow this through with my dealer's Service Manager but how about a petition from like-minded Club members to Lexus GB to sort this out?

I've seen the 'diagnostic' menus on the IS satnav.

There's nothing there to stop the 'greying out' ...

I guess there may be other menus too but my guess is it's in software / firmware.

[andyhart21]

If my memory serves me right, at Gaydon last year, Dave, Rod, Chris and I tried the diagnostic menu in Rodders GS, and there was no way of altering this. I think that was the older CD ROM Sat Nav though am I right Dave/Rod??

I think the diagnostic menu is accesed differently on the DVD Sat Nav systems........

[agalbraith]

What ways do we know of of accessing the maintenance menus on the various systems?

I don't think that discussion of this openly can be violating any warranty / law / friendly agreements with Lexus, surely?

[Rodders_UK]

If my memory serves me right, at Gaydon last year, Dave, Rod, Chris and I tried the diagnostic menu in Rodders GS, and there was no way of altering this. I think that was the older CD ROM Sat Nav though am I right Dave/Rod??

I think the diagnostic menu is accesed differently on the DVD Sat Nav systems........

yeah we did Andy, and I've played with it since - there's no menu option to disable the movement thingy

[DUNCAN]

It may be an idea to test for the hand brake wire at the nav ecu.

Some systems only let you input data when your parked with the hand brake on.

Not sure what colour it would be, but should go negative when brake is on.....

[Leexus]

Found this one on the .net

http://www.is300.net/forum/viewtopic.php?t...0194&forum=17&2

also this one: How to access Secret NAV and Service Menus

http://www.is300.net/forum/viewtopic.php?t...0660&highlight=

[Matthew_McNally]

also this one: How to access Secret NAV and Service Menus

http://www.is300.net/forum/viewtopic.php?t...0660&highlight=

anyone tried this yet on the DVD based sat nav system?

[Geoffers]

Yep - just tried it and it works. You can't do much though.........

[Matthew_McNally]

Yep - just tried it and it works. You can't do much though.........

still cool - I love stuff like this ("The geekiness is strong in this one").

Will try it out later whn I'm in the car.

ps - took care of that duplicate for you mate ( ;) )