tfischer

It's much harder to use an iPhone for navigation than a built in auto NAV system. For one thing, the screen size is much bigger. Actually, that's enough of a list. There are other differences, but that's the big one. The screen is right there showing you where you are all the time. There are advantages to using the iPhone, such as real time traffic and weather, but you can use those features in conjunction with the NAV. And don't forget that the NAV works everywhere, not just in those locations with a good cell phone signal.
I've been using the NAV since I got my SC430 in May of 2001, and although it's quite old by today's standards (and I have seen the new car systems), it still works fine and always steers me in the right direction, maybe just not with the neatest graphics (some of which only use 2/3 of the screen anyway, reserving the rest for a pretty blue sky).
My daughter has an X5 without NAV, but her iPhone will somehow (bluetooth?) give turn by turn directions through the car speakers, which is a nice touch, but leaves her with the little bitty map on the phone screen. I would suggest that if you are going to use an iPhone for nav that you investigate the iPad Mini in order to get a decent image that you can see without taking your eyes off the road for serious amounts of time.
I'm a fan of the built in NAV systems, but they do cost a lot, which is, of course, another factor. The solution there, of course, is to just buy a car with the NAV as standard equipment, because then it's free.

chrisv78

Well, back to the drawing board. Does anyone know how to test if the NAV antenna is functioning? Apparently it is set of a Lexus tests.

Habious

Let's try some stuff.

Do you have a smartphone (iPhone or Android) that could give you a fairly precise GPS location?

I have an Android phone and just searched "Lat Long" in the Google Play store for a free app that will tell me Latitude and Longitude

That gives us some kind of a reference to work with.

Once we have that, let's look at the GPS test screen and compare the two.

You said in an earlier post that you have a 2002, so you should be able to get to the diagnostic screen.

(from the "I agree" screen - Upper-left, lower-left, upper-left, lower-left, lower-right).

Choose GPS (don't pick ANYTHING other than "GPS" or "OVERRIDE" on this screen or you can seriously FUBAR your system - worse than it already is).

How close is the Lat/Long. on the phone app to the Lat/Long on the Nav?

chrisv78

The nav is a gen 4 unit with 12.1 maps. I actually found that screen by accident today and noticed that there were no lat/long data. I could use my phone to enter them though. However I was able to manually calibrate to the correct location as long as I don't travel on roads newer than the maps.

chrisv78

I did have another thought though. I read somewhere that the GPS was triangulated based on both the nav antenna and the radio antenna. Lately I have noticed that the radio antenna is not adjusting. Could that effect the ability of the system to lock?

JohnnyCake

From a logical point of view, my guess is that this says it all. The NAV isn't getting a signal and has no idea where it is.

Habious

I had the same thought when I read that.

Knowing that you've replaced the NAV system at some point, have you verified the GPS antenna connection on the NAV brain?

chrisv78

Checked the error codes using the service mode settings (thanks to a VVTiBob post) and saw code 58-40 in the*12 area. He says it points to the antenna. A GX forum post noted something about a disk error causing the code.

I also got the posit ap for my phone and noticed a bit of a lat/long difference even though the map is spot on. I need to validate the phone.

Still not sure. May be taking another of VVtiBob's posts to heart with an after market media solution.

chrisv78

Well, I think I have finally found the problem with the nav in my car. I think that the antenna had died - I still have not traced the wires from the CPU to the antenna, but know that the antenna was not connecting satellites to the CPU. However, if it is the antenna, a new one is $600 and the labor to install it is 7.5 hours if the shop has the special tool. I had given up, and ordered a new stereo to install in the car to get all of the new tech bells and whistles. I went to the local installer, who told me of a shop to buy the install kit locally.

I called them and asked what the best way to proceed was. I explained my situation, and they said that they could probably replace the nav antenna with an after-market antenna and get all of the functionality back. At least it was worth a try - right? He also mentioned that they would buy the kit from beat sonic - just like me! I drove up to the shop, and the guy grabbed a couple of GPS antennas from the shelf, compared the connectors to the one on the unit, and plugged one in - we almost immediately connected to the satellites. He routed the wiring up to a location underneath the rear seat shelf just above the CPU, and it works. $40 for an antenna and an hour of labor later I am headed home! Pix to come.

kjcole

We love happy endings!

elexusparts

9. START−UP AND FINISHING OF THE DIAGNOSIS
(a) Diagnosis Start−up by touch switch.
(1) Vehicle speed should be 0 km/h (0 mph).
(2) Apply the parking brake.
(3) Turn the ignition switch to ACC or ON.
(4) Push the DISPLAY button.
(5) Activate the screen adjustment screen.
(6) Alternately touch the upper and lower bottom parts
of the left end of the screen 3 times.

SlvBullet

iTrader: (8)

Just read through this. Fantastic results! Thanks for sharing.

JohnnyCake

Can you post your pix/instructions? I think I am in the same boat. And good thing too because the Nav seemed to think that I drove most of the way home in the river today.

chrisv78

Replacing the antenna is really very easy if you don't mind crawling in your trunk. I wish someone had talked about this before I paid someone $85 to do it for me!

You'll need to find a nav antenna with a single pole connector, preferably with a magnetic base, and a cord that is 2 or 3 feet long. I just checked eBay, and there are a few available that look like they would work.

The hardest part of the trade out is to get to the nav dvd unit in your trunk. There are some really good instructions on the forum that describe updating the nav dvd from a gen 2 to a gen 4. Basically, you take most of the carpet out of the trunk, unbolt the two braces over all of the electronics, and then unbolt the 3 bolts that hold the nav unit in place. It looks like an old dvd player.

Once it is loose, there are several cables in the back. The smallest (single pin) is the connection to your antenna. If you haven't already bought one, look at the plug - it is a trapezoidal shape with a small wire in the middle - that is what you need to match to make this work.

Once you have the right antenna, you can plug it in to the dvd unit, place the antenna outside the trunk, and boot up. You should see the GPS letters on your screen. Let the car run several minutes before you decide it didn't work. For some reason mine took a while to realize that there was an antenna there.

Once you have that going, disconnect the antenna. There is a nice shelf right above the vertical carpet at the trunk that has no metal between the shelf and the sky, just plastic and the window. That is where you can locate the magnetic base. Fish the wire down the back carpet, secure it, and plug in the antenna. Fire up the GPS again to make sure you still have signal. You may have to move the antenna a little for best results.

From there, just reinstall the carpet and you should be good.

I will try to get some pictures, but I am SO tired of pulling the trunk carpet after the several things I have done back there!

JohnnyCake

I purchased a replacement on eBay but am concerned that the plug is square, not a trapezoid. Don't want to get the trunk all torn up and then have the wrong part -- does this look right?