Nav problem
09-08-06, 03:17 PM
#1
Super Moderator
Thread Starter
Nav problem
This has happened to me twice now; once a few weeks ago, and again on the way home from work today.
Both times, I glanced down at the map, only to see a location wildly off from my actual location -- probably off by 3 to 5 miles. The first time it looked like I was blazing through fields, the second time it looked like I was jumping around on various (wrong) roads. Both times, I powered off the car in the hope that would fix it, but it didn't. So I used the calibration function to reset the map and direction to my actual location, and things seemed fine after that.
Has anybody else ever experienced this kind of glitch?
Both times, I glanced down at the map, only to see a location wildly off from my actual location -- probably off by 3 to 5 miles. The first time it looked like I was blazing through fields, the second time it looked like I was jumping around on various (wrong) roads. Both times, I powered off the car in the hope that would fix it, but it didn't. So I used the calibration function to reset the map and direction to my actual location, and things seemed fine after that.
Has anybody else ever experienced this kind of glitch?
09-08-06, 05:12 PM
#2
Tech Info Resource
iTrader: (2)
09-08-06, 05:19 PM
#4
Super Moderator
Thread Starter
Thanks for the pointer to that thread. I went to the diagnostic screen, and it appears that the nav is only seeing two satellites at the moment. Not sure why this would be, as the weather is clear. If the problem persists, it's off to the dealer.
09-08-06, 05:26 PM
#5
Super Moderator
Thread Starter
No, I've overridden the nanny with the menu-volume-top-bottom-top-bottom trick, but I've never pulled unit out nor touched the wiring.
From the thread the other day, I learned that my car wasn't made at the Uhura or Tahini or whatever the heck that award winning assembly plant is called. Perhaps the nav installer at the second string factory was busy shmoozing with a co-worker as my car went by.
From the thread the other day, I learned that my car wasn't made at the Uhura or Tahini or whatever the heck that award winning assembly plant is called. Perhaps the nav installer at the second string factory was busy shmoozing with a co-worker as my car went by.
09-08-06, 07:58 PM
#6
Bichon....I have noticed it twice now myself, and have been meaning to post about it. That link has some good information, in fact I had already reset my unit, and checked how many satellites I had aquired at that time.
I have now been keeping track of when my system actually has a valid gps signal simply by seeing the "gps" under the scale marking/compass arrow. When you see "gps" it has a valid signal. Very soon after I see that the car finds its location pretty quickly.
I also am thinking that my car has over 25k on it and the accuracy of the dead reckoning is fading away with my tires....Ill see how things change when I get my new tires....
I have now been keeping track of when my system actually has a valid gps signal simply by seeing the "gps" under the scale marking/compass arrow. When you see "gps" it has a valid signal. Very soon after I see that the car finds its location pretty quickly.
I also am thinking that my car has over 25k on it and the accuracy of the dead reckoning is fading away with my tires....Ill see how things change when I get my new tires....
09-08-06, 08:23 PM
#7
Tech Info Resource
iTrader: (2)
I did some digging into this tonight because I've seen my position off by a hundred yards or so when I got in the car after one of our spectacularly hot days (110F+) last summer.
This problem has three possible sources according to Toyota - first
Next -
Finally -
If the first test fails, troubleshoot the circuit between the combination meter and the multidisplay. If the second test fails, replace the navigation ECU. If the third test fails, repair the wire harness and if that does not fix the issue, replace the multidisplay.
Oh, yeah, in the troubleshooting table, they list being able to work the nav buttons while moving as a fault...
This problem has three possible sources according to Toyota - first
While driving, compare the "Speed" indicator to the reading on the speedometer. Check if these readings are almost the same.
OK:
The readings are almost the same.
OK:
The readings are almost the same.
Disconnect the navigation ECU connector p2.
(b) Measure voltage.
(1) Jack up either one of the drive wheels.
(2) Move the shift lever to the neutral position.
(3) Turn the engine switch on (IG).
(4) Measure the voltage between terminal SPD of the
navigation ECU and body ground when the drive
wheels are turned slowly.
OK:
Voltage pulses as shown in the illustration.
(b) Measure voltage.
(1) Jack up either one of the drive wheels.
(2) Move the shift lever to the neutral position.
(3) Turn the engine switch on (IG).
(4) Measure the voltage between terminal SPD of the
navigation ECU and body ground when the drive
wheels are turned slowly.
OK:
Voltage pulses as shown in the illustration.
Disconnect the multi-display connector p1 and
navigation ECU connector p2.
(b) Measure the resistance according to the value(s) in the
table below.
navigation ECU connector p2.
(b) Measure the resistance according to the value(s) in the
table below.
Oh, yeah, in the troubleshooting table, they list being able to work the nav buttons while moving as a fault...
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09-09-06, 05:08 AM
#8
Pole Position
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Bichon, before you go to the dealer, understand some limitations in the nav system.
First, the fact that the diagnostic says only two satellites are being seen doesn't necessarily mean there is a problem with the car's nav system. Remember, those satellites move in the sky, and it may be that they are in a position where the best signal is simply not being sent to the car.
Also, the reason your position was off on the map was because there was no satellite signal to give you the correct position. I'm not sure how the system in the IS works, but in my Lincoln, when satellite signal is lost, the system figures your position based on dead-reckoning (e.g., measuring speed and distance). Any errors in that calculation can result in a false position.
Its likely the problem will correct itself once a stronger sat signal is received. However, if it repeats, I'd ask the dealer about it. Best of luck.
First, the fact that the diagnostic says only two satellites are being seen doesn't necessarily mean there is a problem with the car's nav system. Remember, those satellites move in the sky, and it may be that they are in a position where the best signal is simply not being sent to the car.
Also, the reason your position was off on the map was because there was no satellite signal to give you the correct position. I'm not sure how the system in the IS works, but in my Lincoln, when satellite signal is lost, the system figures your position based on dead-reckoning (e.g., measuring speed and distance). Any errors in that calculation can result in a false position.
Its likely the problem will correct itself once a stronger sat signal is received. However, if it repeats, I'd ask the dealer about it. Best of luck.
09-09-06, 12:49 PM
#9
Not to be a *** but just want to clarify as to not misinform the rest of the community, the satellites are actually geosynchronous, meaning they DO NOT move in the sky, they are stationary. They send a constant "beep" our, and all gps receivers pick up this timed "beep" and compute the relative change between "beeps" and estimate the gps receiver's position relative to the satellites. It is VERY true that if the signal is degraded by physical objects i.e trees, bridges, tunnels etc. the gps will give an incorrect or inaccurate position, which is what I believe is happeneing with my gps, and probably other's too.
09-09-06, 01:16 PM
#10
Lexus Champion
Not to be a *** but just want to clarify as to not misinform the rest of the community, the satellites are actually geosynchronous, meaning they DO NOT move in the sky, they are stationary. They send a constant "beep" our, and all gps receivers pick up this timed "beep" and compute the relative change between "beeps" and estimate the gps receiver's position relative to the satellites. It is VERY true that if the signal is degraded by physical objects i.e trees, bridges, tunnels etc. the gps will give an incorrect or inaccurate position, which is what I believe is happeneing with my gps, and probably other's too.
09-09-06, 04:31 PM
#11
09-10-06, 03:56 PM
#12
Super Moderator
Thread Starter
I've been keeping my eye on the "GPS" logo on the scale marker, and I'm sorry to say that it has been off WAY more than on this weekend. (Though the vehicle speed sensor and gyro appear to do an amazing job of plotting my position on the map even though the GPS signal is out)
Does anyone know for certain where the GPS antenna is located? I've seen a few threads that claim it is by the rear view mirror, and one that claims it is under the dash, but I'd like to know for sure. Perhaps some wire jiggling could save me a trip to the dealer.
Does anyone know for certain where the GPS antenna is located? I've seen a few threads that claim it is by the rear view mirror, and one that claims it is under the dash, but I'd like to know for sure. Perhaps some wire jiggling could save me a trip to the dealer.
09-10-06, 08:48 PM
#13
Tech Info Resource
iTrader: (2)
Do the Info switch hold for three seconds, and click the parking lights on and off. The menu that comes up will show any logged errors. It also may not show any errors. Press the LAN check button in the lower left corner. Now you may see errrors for the NAV system (at least I see that on mine). If the button is orange, press it. It will have the codes.
If the detected error is the antenna, you'll see either code 58-41 or 80-41. If the error is not one of these two, then it might not be the antenna at all.
If you want to try checking the antenna connection, it is the yellow wire on connector A pin 13. The antenna itself is in the center of the dash at the front. Is it possible you have a radar detector or some other device directly over the antenna blocking the signal? (Yeah, I know it sounds really dumb, but I figured it can't hurt to ask.)
If the detected error is the antenna, you'll see either code 58-41 or 80-41. If the error is not one of these two, then it might not be the antenna at all.
If you want to try checking the antenna connection, it is the yellow wire on connector A pin 13. The antenna itself is in the center of the dash at the front. Is it possible you have a radar detector or some other device directly over the antenna blocking the signal? (Yeah, I know it sounds really dumb, but I figured it can't hurt to ask.)
