Lane Keep Assist comments

I've had mine for 4 months now and I experience the same thing. The road will be clearly marked (no exits or interuptions) and for no reason I can identify, LKA shuts down. It starts again in a few seconds. Same problem. Another, even more puzzling behavior is that my LKA will sometimes keep working when the right markings are not there.

There is a stretch of road I travel a couple of times a week. For about 1/2 mile shoulder repaving has covered up the right side line. The double center line is intact. Without fail LKA keeps working even though it can't "see" any markings on the right.

I would love to understand what is happening.

 

I share your experience. The combination of those features (though I think the DRCC is most responsible) leaves me much more relaxed at the end of a trip.

For those who think LKA will cause accidents...well sounds like the same stuff I heard about cruise control. Remember? People said that drivers would "forget" to hit the brakes, etc. It turned out the opposite was true. People hit the brakes sooner when using cruise control.

My bet is that DRCC and LKA will reduce accidents. Aside from the obvious benefits like avoiding rear-ending the car in front when there is momentary distraciton, there is the very significant benefit of allowing the driver to remain alert and comfortable by avoiding the significant fatigue of constantly adjusting speed and position on a highway (not a city street).

 

Due to our extended experience with LKA dropping out so often (justified or not) on a round trip from San Diego to Napa Valley, my wife came to the conclusion that Toyota purposely designed it to provide constant visual and audio feedback to the driver at semi-random intervals. As such, we now simply view LKA as a driver alert system.

So, once one accepts the quirks (or annoyances) of LKA and uses it accordingly, it definitely serves as a Toyota driver safety assist system (DSAS).

As for DRCC, this technology empowers the driver to more fully appreciate the joys of an extended road trip and driving experience.

 

As I posted previously my LKA really doesn't drop out much at all and when it does the reason is usually obvious. I suspect that those of you with LKA drop out problems may need to have the camera realigned? If you have time why not take the car in? I'm sure it would be a warranty item and it would be interesting to see if it helps or not.

 

I agree with this. I have drop-out of the LKA on a fairly regular basis, but it doesn't come as a surprise to me. Usually, the reason has to do with faded or missing lane markers. The other common reason is having sunlight hitting the lens. This happens when the sun is low in the sky and somewhere between 10 and 2 o'clock (directionally, not time measurement). Less common is the instance of reflection -- too much water on the road or something competing as a light reflector/emitter.

 

Did they align the camera? That may be the only way you can know if it's right or not. Some guy driving it and saying "everything's OK" or "don't worry they all do it" may not be not good enough. Chances are the guy who drove it and pronounced it OK has never used one before and has no idea how it should perform. Having it not work right is not a safety feature. They may have just given you the brush off because they didn't want to learn how to do the job correctly. This is typical of service departments.

The Toyota TIS site has a procedure for camera alignment and it would be in the maintenance manual as well. If you have time you might consider finding a service department that will agree to do the job correctly. Tell them you would like to have it aligned in accordance with their procedure not just taken for a test drive.


EDIT: Tony, after reading A Priory's post below I think he may be right and the camera alignment may not be the problem. Anyway I hope you can find someone to fix it for you because it really is a good system when it is working correctly.

 

It is possible there may be an alignment problem, but maybe not one where the camera is mis-aligned.

During the course of one of the recent repairs to my car, I talked with the body shop about the status of the repairs. He said it had gone to the Toyota dealership for a four-wheel alignment. I asked whether they could have done it, and he said they normally would have, but because of the AT Package (the LKA, specifically), they wanted it to go to Toyota. I asked why, and he said the LKA would not work properly if it wasn't aligned with the car's proper alignment.

I think there were two parts to this. One had to do with the camera anticipating the proper position for the lane markers. (From the LKA computer's perspective (or so I am imagining), the lane markings should "stay" in certain places, and corrections would be made through steering adjustments, to try to get the lane markings "back in place."

The other issue had to do with disconnecting the 12V battery. I don't know what would be lost, but it seemed to have something to do with the LKA alignment and how is related to the wheel alignment.

OK . . . I don't know much about this, but I thought I'd pass along some of what I had heard earlier.

 

That makes perfectly good sense. There is a steering sensor for the VSC as well (possibly the same one) because it also needs to know which way the steering is pointed.

I downloaded the 4 wheel alignment procedure when I had access to TIS and it cautions the technician to "Perform zero point calibration of the yaw rate and acceleration sensor and test mode inspection." after the alignment is completed.

I know the cars sometimes get banged around a bit in transit, the alignment on my '05 was completely out of spec when I got the car and it only had 3 miles on it.

That could easily be the reason the LKA is not performing exactly right on some cars and it seems just fine on others. On my '05 I was told that Toyota would do a free 4 wheel alignment within one year of purchase for that reason. Not sure if that policy is still in effect or not.

 

I would think proper calibration for the VSC is much more critical. I also think the VSC is tied to more of an inertial sensor, while the LKA is linked directly to a video feed. The former is likely to be more dependent on a "true north" setting.

It was in effect for my 2007. I don't know about the 2010. I've already had mine done (thanks to accident 2 of 3), so I may not have it checked out at the 10/15k service.

 

My experience with our new V with ATP is similar for the LKA. I like the feature, but it seems to drop out far too frequently to really make safe use of on busy roads. The DRCC on the other hand is very useful and has proven to be a big safety feature. It has applied the brakes when someone suddenly decided to stop to make a turn off a main highway. So I'm very pleased with this feature. The parking assist is the most useless feature ever added to this or any car as implemented. By the time you properly set up the feature, you would run the risk of an impatient driver giviing you the finger or worse. Any feature that takes as many pages to explain with the disclaimers is just useless. I'd far rather have had auto headlights and electric seats or blind spot warning than this feature. And no I'm not unhappy with the car. Far from it. This is our second Prius as well as also having a Camry hybrid which we are both extremely happy with, I just feel Toyota felt they had to throw in this to justify the high price of the ATP.

 

Problem is most of us never test the VSC, whereas we test the LKA when we use it. But both systems need a steering input. The VSC does use a yaw sensor and a g force sensor but it also uses a steering turning angle sensor to tell which direction the front wheels are pointed so it can determine what to do with the throttle and individual wheel brakes if needed. The LKA is going to give the driver an input via the steering to nudge the car back on course only if the steering is not already positioned to do so.

Galaxee and DH told us that the steering sensor needed to be adjusted any time there was an alignment, which goes along with what you said as well. But that was for the Gen2 which had only VSC. I had to have mine reset a couple of times on the Gen2 due to my alignment problems.

 

I agree with your assessment of the Parking Assist. I think Priori said he was using his now! Wish he was closer I would have him teach me how.

I also find the DRCC to be a great option but I think my LKA is a little better than some it doesn't drop out without reason. Hope I never get to try the pre-collision system.

 

I said I'm testing it out! I've never actually used it to help me park in any kind of busy world. I have been going through the MANY pages of instruction, and I am learning a few new things. (The first thing was that the Owner's Manual's only reference to it was the name of the button on the dashboard! The instructions are in the NAV book.)

Don't forget to look at these instructions! Another thing I found out is that you can use the feature in a kind of "quick" form -- look for the icons on your screen when you put the car into reverse. You can always press one of those buttons and start using one of the features.

If you DO get the pre-collision system to work for you, you will be VERY happy to have it. I had it go off on me twice within the first two weeks of owning the car. In the next 7,000 miles, it has not been activated again.

 

Just picked up our V with AT pkg. We had been waiting over a month for a IV w/solar pkg and upon investigation broadened the cars we would take to include the V w/AT. The KLA feature really works and coupled with the DRCC make the car much safer. My wife is trading down from an SUV and safety was our primary reservation about buying a car the size of the Prius. We travel alot and I believe the Prius with these features add up to a very safe car. Could not be happier and sure enjoyed filling up after the 62 mile trip from the dealer and only paying $2.50, wow!! I have never had trouble parking large SUV's so parking anything the size of a Prius should not be any trouble, but my wife will enjoy the parking when we get more comfortable with the car. Another big safety feature of the new Prius is the bluetouth cellphone. Programming is easy...we even downloaded our contacts. Enough of my ranting...time to get some sleep so we can enjoy our new car tomorow....wife is taking to the coast for the weekend (1,000 mile round trip).

 

:welcome: Welcome to PC and congratulations on your new Prius. The V with ATP is a good choice DRCC and LKA make trips a lot more enjoyable.

 

This is a recommended read.
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_H*

 

DISAGREE with 98% of this article!!! He'd like us to go back to the 20s.

David (aka Blind Guy)

 

Thanks Hobbit that was a good article, in spite of the fact that I bought a ATP equipped Prius I agree with at least 75% of what the author had to say.

I was especially interested in his comments about speed sensitive steering. I had an '84 Honda Prelude which had the best steering of any car I have ever owned, maybe one of the best steering cars ever made. It had speed sensitive steering, the power steering started to go away gradually at about 15 MPH and by the time you reached 25 or 30 you just had manual steering. But unless you knew this in advance you wouldn't know it had happened, you would just think wow what a great steering car.

 

New V owner here with ATP. When using the LKA, it seems it wants to pull me right to the edge of the line and then will abruptly go to the other side, occasionally crossing (and beeping bloody murder) the line. It seems like it is trying to keep me OUT of lane. I imagine this isn't normal, particularly watching the LKA demo on youtube (granted it's a lexus but same technology) where minimal steering inputs were done.

Comments? Suggestions? Thanks!