Sat Nav

[alien1974]

my sat nav cant locate the car on the map any ideas how to fix this

[cruisermark]

this points to a possible dislocated GPS sensor which is located behind the sat nav unit deep inside the dash somewhere - hope someone provide a bi more informtion than me

[Keith Bowler]

Had a similar problem with mine which turned out to be a faulty hard drive due to a damp boot.

Replacing the hard drive solved the problem straight away.

I was advised by a reputable auto electrician that very rarely does the GPS sensor fail.

[alien1974]

Thanks for the replies, the boot is bone dry, i have the discs would it be worth trying to re install them?

[Bluesman]

Definately cant hurt to reinstall them. Mike

[n4chv]

I have removed and then re-inserted the Sat Nav Disc from the changer and there is also a reset function on the Sat Nav which should recalibrate the position

I've not heard of the GPS Sensor failing in these cars before

[alien1974]

update- the clock automatically updated itself so the gps must be ok, i know its had new tyres recently which apparently causes problems according to the handbook, but it doesnt say how to solve the problem if this happens, i took the disc out and reinstalled it, should i take out the 2 audio fuses and reinsert them? i am stumped on this one!

[Malc]

how on earth can new tyres create the problem .......... pray tell !

Malc

[ambermarine]

I was out this weekend going south on the M6, at Tebay services and did'nt turn on My satnav until then, some 160 miles from home.

The satnav put me in Perth and we drove for some 25 miles south before it finally located our correct position .

I suspect from my experience that your unit as become disentoriated ,I would re-install the whole set up wipe your home from the memory in the set up procedure and start all over again with a virgin installation if that does'nt fix it something is amiss in the unit.

[Tulpen]

Malc,

New tyres can cause a problem with the OEM GPS (although not the one mentioned by OP)

The GPS calculates things like distance travelled by the tyre diameter and needs to be recalibrated if new tyres are fitted.........or it does on the LS 460, according to the manual.

[Malc]

good lord ......... what a palarva ................. what if you irreparably damage only one tyre and replace just that one ?

Malc

[alien1974]

just found a section in the owners manual saying take to lexus dealer after having the tyres replaced ahh well hmm

[Malc]

Nail in the coffin for me getting a 460 then ............ keeping my Ls400 absolutely forever now ( fingers xd )

why oh why do they make life so abysmally difficult for us poor Ls owners ( rhetorical Q no doubt )

Malc

[alien1974]

Malc same issue for the 400 though

[Tulpen]

Malc,

I think part of the thinking may be that, if you can afford to buy a new LS, you are not 'poor'. :)

However, for people like you and I who buy them (quite) a few years down the line, the bills can make your eyes water.

While I agree with your sentiments about keeping your LS 400 'forever'.......there will come a day when it will become un-economical. Because of moving to Holland, I was forced to get rid of my 400 and bought a 460. It is a magnificent car but there are a lot more things to go wrong :(

[thelawnet]

You don't have to go to the dealer after new tyres, only if you have changed tyre size. Even then I don't think it would cause the GPS position to be out like that.

I fitted my own GPS in my VW, and maybe the sensor isn't in the right place but I don't get the best signal - GPS uses trilateration, whereby your position is calculated using the intersection of spheres - and if you don't have a signal from sufficient (at least 4) satellites, your position will be inaccurate.

[Malc]

Malc,

I think part of the thinking may be that, if you can afford to buy a new LS, you are not 'poor'. :)

However, for people like you and I who buy them (quite) a few years down the line, the bills can make your eyes water.

While I agree with your sentiments about keeping your LS 400 'forever'.......there will come a day when it will become un-economical. Because of moving to Holland, I was forced to get rid of my 400 and bought a 460. It is a magnificent car but there are a lot more things to go wrong :(

Malc same issue for the 400 though

Well, I guess the real problem is having GPS then ........... if I continue not to have it then all will be well.

My satnav is either the g/f, which is quite challenging at times, or her TomTom or maybe just chill out, take life easy and ( like I did in Spain and Portugal on holiday ) just go where the car decides to take me ........................ .... with the occasional help of paper maps

Malc

[Fringfordjohn]

Being new to this forum I’m not sure if this has been mentioned before, but I had exactly the same problem with my 1999 Mk 4.

The problem first manifested itself about two months ago when I was driving to an obscure address in Coventry. I didn’t switch the sat nav on until I stopped for petrol on the A45 just outside Coventry, but when I did it was telling me that I was still outside my house just outside Oxford. I managed to zero it back in using the calibrate function, but it wandered off course again within a couple of miles. Bit of a nuisance really as I was relying on it to find my destination, but luckily I had an Iphone with me so I was able to use the sat nav function in that instead.

Over the next month I tried zeroing it in to my current location several times, but each time it would only last for a few miles before wandering off track again. I assume this was because the car was using only the “dead reckoning” part of the system where it works only by knowing the direction of travel and by counting the turns of the wheels, hence the problem if you change the tyres. All this time the GPS logo on the screen was not lit.

However whilst scouring this forum, and the Club Lexus one in America, I chanced on the method of accessing the so called “secret menu” (Climate and Audio held down together and turn the lights on and off twice, with the ignition in the auxiliary position)

When I did this a screen that I had never seen before appeared and then the car went through as series of checks including one for the sat nav which it declared to be OK. If you then select sat nav on this menu another screen appears and one of the options on it is GPS check. On selecting that, a number of vertical columns of numbers appeared, and as I sat watching them they were flickering and changing. I didn’t really know what I was looking at, but it did look like it might well have been satellite reception.

You then have to press the map button to exit this menu, and when the map screen appeared it now showed the car as being in the correct position, which it wasn’t when I started, although the GPS icon was still not lit.

However the next time I used the car, the GPS icon reappeared and the sat nav was working correctly, and it has continued to do so ever since.

Not sure if this will cure Matthew’s problem but it certainly cured mine, at least for now.

[alien1974]

Being new to this forum I’m not sure if this has been mentioned before, but I had exactly the same problem with my 1999 Mk 4.

The problem first manifested itself about two months ago when I was driving to an obscure address in Coventry. I didn’t switch the sat nav on until I stopped for petrol on the A45 just outside Coventry, but when I did it was telling me that I was still outside my house just outside Oxford. I managed to zero it back in using the calibrate function, but it wandered off course again within a couple of miles. Bit of a nuisance really as I was relying on it to find my destination, but luckily I had an iphone with me so I was able to use the sat nav function in that instead.

Over the next month I tried zeroing it in to my current location several times, but each time it would only last for a few miles before wandering off track again. I assume this was because the car was using only the “dead reckoning” part of the system where it works only by knowing the direction of travel and by counting the turns of the wheels, hence the problem if you change the tyres. All this time the GPS logo on the screen was not lit.

However whilst scouring this forum, and the Club Lexus one in America, I chanced on the method of accessing the so called “secret menu” (Climate and Audio held down together and turn the lights on and off twice, with the ignition in the auxiliary position)

When I did this a screen that I had never seen before appeared and then the car went through as series of checks including one for the sat nav which it declared to be OK. If you then select sat nav on this menu another screen appears and one of the options on it is GPS check. On selecting that, a number of vertical columns of numbers appeared, and as I sat watching them they were flickering and changing. I didn’t really know what I was looking at, but it did look like it might well have been satellite reception.

You then have to press the map button to exit this menu, and when the map screen appeared it now showed the car as being in the correct position, which it wasn’t when I started, although the GPS icon was still not lit.

However the next time I used the car, the GPS icon reappeared and the sat nav was working correctly, and it has continued to do so ever since.

Not sure if this will cure Matthew’s problem but it certainly cured mine, at least for now.

Thankyou for the reply John this is the exact problem i have i will give it a try

[alien1974]

Right i tried doing what you said, i am getting all of those numbers on the gps page, but when i press map nothing happens, the only way i can come out of it is to switch off the ignition, there must be some sort of glitch in the system hmm so i have decided to pull and put back in fuse 16 and 35 is that all i need to do to reset the nav system?

[Fringfordjohn]

Hi Matthew,
Sorry you’re still having problems. Regarding the fuses I’m afraid that I have no idea as my knowledge of these cars doesn’t extend that far. I don’t see that it can do any harm however so I can only say try it and see. I would be interested to know the result in case my car starts playing up again.

After reading your post last night I have gone through the whole routine again this morning, and it works exactly as I said in my previous post, including the bit about pressing Map to exit. I really can’t explain the difference between the cars, the only thing that comes to mind is that as my car appears to be a year later than yours, has it got different software loaded in the sat nav computer.

The other curious thing about all this is that both the the sat nav and the GPS icon didn’t start working again until the next day after I had completed the above checks, although this might have been because the car was in the garage when I was doing the initial check which might have been weakening the signal.

Sorry I can’t be more helpful but I don’t know what else to suggest. The above procedure got my sat nav working again and I was hoping it would do the same for you. If you do manage to get it going again, I’d love to know how you did it.

Kind regards

[alien1974]

Fixed it!!! all working now, turned out the date on the nav was set for 1995!! as soon as i put the correct date in the gps logo came up and it found my position, well happy now!

[Fringfordjohn]

Hi Matthew,

Been working the weekend, so only just spotted your post.

Really glad that you have got it fixed, and well done for finding out how to do it. Mine is still working at the moment, but if it gives any further trouble I'll know the first thing to check.

Thank you again for posting your solution

Kind regards