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I was quite puzzled about what was causing this since it is often the GPS system "itself" that put me on, guided me too, the street I am currently on when it decides I'm on a parallel street.
But then I happened to be driving in one of our mountainous areas and the system kept repeating, again and again, the same directions.
I now think that what is actually happening is that the system is momentarily losing contact with one of the three GPS satellites it requires for operation. Once it regains contact it completely resets its past memory and recomputes your location. Since it now has no past history you may end up anywhere within the system's accuracy tolerance.
But from the information I have, I think GPS precision (or lack there of) and the error-correction algorithm are still the main cause behind the "parallel street" phenomenon.
With the sole exception of for some reason having "lost" my current position, momentary loss of 1 GPS signal, and then having to recompute. The symptom is so widespread, and has existed since my 2001 RX300 was built, that it cannot be something like a temporary interruption of power.
Now, the trouble comes. After a few seconds, the new GPS calculation shows the car to be 1' from the middle of the two roads, leaning toward road A. Does the algorithm suddenly thinks that the car is on road A, but should it change the display to road A?
In this scenario, that would be correct. But what if the opposite happens? What if the GPS was correct all along, but the new calculation suddenly shows the car to be on an adjacent, parallel road? Should the system "jump road"?
As a result, the program has no way to know if it should jump on the new calculation, since it doesn't know whether the one before was correct to begin with. So no matter what the programmers decide to do (whether to jump on new information or not), the algorithm is bound to fail occassionally with inaccurate GPS feed. And it is my guess that Toyota / Denso decided that it is best for the system to only use the latest data and calculation, perhaps with a small degree of reluctance in the program to "jump roads," and hope for the GPS signal to be as precise as possible.
In a perfect world, where the GPS signal and the DVD data are both completely accurate, the map program would be ridiculously to write. Given the long / lat, load up that section of the map, and there you have it.
From my experience dealing with GPS, I would say Toyota / Denso is already doing a pretty darn good job. I bought a standalone GPS reader a while ago, which rumored to be made by the same OEM that works with Denso / Toyota. My faith in GPS was somewhat shattered after I hooked it up to the computer and started taking in the readings. Not only did it require almost 30 seconds to warm up (on a good day) and acquire the minimum of 3 satellite signals, the calculations jumped so wildly that it was impossible to know exactly where I was and at what altitude. I stood there on my drive way and the system showed that I was bouncing around the block over a pretty big area, and my altitude bounced somewhere between 260' and 320', non-stop.
So the fact that the GPS in my Avalon has only put me on the wrong road once in the past 3.5 months and 3500 miles, I'm already very happy with the algorithm.
IMMHO the system couldn't work at all, given the tolerances involved, if it didn't have a "look backward" routine to validate the current computed location.
It's sort of like taking four readings, computations, of position, throwing out the two most deviant from the previous computation, and using the two that appear to most closely match a "reasonable" computation.
Were I in control I would advise the programmers that in the event of a lost signal then wait a few 100 milliseconds before "reseting" the past known information.
http://members.cox.net/n0v8or/valve_train.jpg
While all this was going on the right side air vent control, the verticle wheel, is almost fulsh with the dash. The directions state the assembly has to be installed a certain way or this would be damaged. Some day I'll get enough of this poor control and ask that it be removed for the third time and fixed right. ange1
One would think that oil cannot fully drain out of the plunger after the engine is shut down. If some oil is retained within the plunger mechanism, at cold start-ups this mechanism would not be dry and the oil pressure would very quickly rise to operating levels.
Independently of lubrication, could it be that as the engine warms up, different expansion/contraction properties of metallic parts cause variable gaps in clearance, and thus the tapping sounds?
havalongavalon
havalongavalon
This is kind of like giving a person an SAT exam but with a few words taken out of each question. You can't possibly expect the person to get 100% on it.
Thanks
Tony
I found this website on Avalon aftermarket grille.
Anther time it commanded --turn right and go one eight of a mile and turn right. I did this and it directed me in a circle right back where I was. I guessed I should turn at the first right which was 100 ft. away. My guess happened to be the right turn. Most of the time it works as expected.
I am finding it takes several minutes for the GPS to turn on before it picks up. I am told the satellites require a little time until they zoom in. This is clear countryside terrain, no buildings or hills.
Somehow, I have the feeling that we're talking about somewhat different things.
It's normal for GPS to require up to a few minutes to acquire sufficient satellite signal to begin its calculations. When I played with a stand-alone GPS receiver, it usually took anywhere between 15 seconds to 4 minutes, depending on weather condition, line-of-sight, interference, etc.
Thanks,
D.
Interstingly, the VIR part usually shows both this fob and another and the price of the whole thing isn't much more than some people have quoted for the fob alone. I am wondering if that device includes a key. Obviously it makes no sense to order that for a fob -- it was just interesting to see the closeness in prices if a key is in fact included.
Thanks,
D.
Thanks,
John
Now for my Question.
When operating in Laser Cruise mode and you approach a vehicle to the front, does everyone's LCC back off real abruptly or do you get a smooth deceleration? It doesn't seem to matter which range I use although at longer range the deceleration is slightly less abrupt. And what's with the 5 mph jumps in speed increase? I find myself dropping back to normal cruise control mode more often than not.
Thanks,
John
Interesting reading at http://www.toyotanation.com/forum/showthread.php?threadid=102636
One post is particularly interesting, because the writer discusses "complete loss of gear" which I experienced too. Copy of post is below:
"Since purchasing the Avalon in early June, I have been frustrated with how the car operates between 20 and 40 miles per hour. The car does not always know what gear it needs to shift into. It will frequently race 1000 rpm ahead without any change in speed. Then suddenly it will accelerate and the rpm’s will drop back to normal rpm.
It seems to happen most often in rush traffic when trying to change lanes. The hesitation in acceleration will cause me to lose most of my margin of safety in the process of changing lanes. In this regard, the car is not safe. There is no way to predict when the problem will occur, and therein, lies the safety hazard.
It would seem that the last effort by the service department to update my computer programming failed to achieve any level of improvement to my satisfaction with one exception. Since the last computer upgrade, I have not experienced the complete loss of gear at high speeds.
Is this a problem in all 2005 Avalons? Is Toyota aware of the problem and do they plan to resolve it?
Serviced on Friday, October 21. Toyota reset the computer learning back to factory default. Technical support in CA explained that there are no current plans to address the issue. Once the learning process develops a bad pattern, it must be reset back to factory default and the relearning started over."
And to think the smug Canadian Toyota dealers, at least in B.C., will not even budge from the excessive MSRP and act as though they are doing you a huge favor to even sell you one of these rigs, is a real trip!
Glad I did not get suckered into buying one and my sympathies to the rest of you who did.
:lemon:
It seems like the Avalon would do the same thing? Since it also "learns" how you drive? Anyone tried it?
Yes, the laser cruise control is rather abrupt sometimes, but not always. Even worse I think is resuming speed, which often invokes a downshift of 2 gears, lots of noise and fuss. This happens especially when you are going uphill. They need a more intelligent controller.
Despite all that, I still like the LCC. Use it all the time on high speed freeway cruising (I5 on west coast). The 5 mph increments initially bugged me, but now I like them because it's easy to adjust to changing speed limits for road construction, etc. When the limit drops from 70 to 55, just 3 quick taps and you're in business.
Max
Normal cruise adjust is 1 MPH per tap. While in LCC, 1 tap will get you to the next speed equally divisible by 5. This was by design according to Toyota.
While in lower n.j., the navigation stopped working. No voice commands. Later looking at the manual, this turned out to be a limited guidance area.
I checked info re GPS on the internet and found helpfull data.One article stated to be really accurate you need two units, one to correct the signal errors, and the other to track you.
I would guess 99 out of 100 times the gps starts right up.
I am learning to accept some of the little things that are not perfect. My wife and I now bet on will the gal give us the right directions.
My manual shows the map data to be a bit old---2003 by Navteq. Two year old data seems to be a bit old for our highly technical world. I am not whining, I just tell it like it is. ange1
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