Impala Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter #1
Hello all,
Our 2016 Impala LTZ2 has now about 6500 miles on it. Recently we've experienced something VERY odd with the Adaptive cruise. We'll be going along just fine, and will come to a slower vehicle that causes the AC to slow the car. From what sounds like the drivers front corner of the car, is this quick "RRRRRRR" that sounds like you are running over a small piece of that serrated road like they put on the left shoulder. When it does it, the car slows a bit as if I tap the brake. It's a bit unnerving. Anyone else experience this? Perhaps it is something to do with the anti lock module but sure seems like it shouldn't do it. Plus it does it so infrequently, I would doubt taking it in, they would be able to replicate it.

Thanks,

John
 

·
Registered
Joined
·
13 Posts
My first thought is that it's braking rather hard if you came up on the slower vehicle rather quickly and the front brakes tend to take more of that load than the rear. Just a quick stream of thought....!
 

·
Registered
Joined
·
75 Posts
Discussion Starter #3
My first thought is that it's braking rather hard if you came up on the slower vehicle rather quickly and the front brakes tend to take more of that load than the rear. Just a quick stream of thought....!


No, it never does it during hard braking, just very light braking. Perhaps it's the antilock brake system pre-charging? I am guessing the anti lock brake system is what controls the braking for this system..
 

·
Registered
Joined
·
13 Posts
After several more trips since my last response, I have experienced the same effect as you mentioned in your initial post. While it doesn't happen every time we come upon a slower car, I have had the experience and I'm chalking it up to the operation of the systems involved. I do notice it more when the brakes seem to apply more abruptly.

I'm still amazed at how well it works and how easy it is to become lulled into a slower speed than what it's set at because you gradually come behind a slower moving vehicle. You have to be watching your own speed constantly.

Follow-up question: when the AC does slow the car, do the brake lights come on??
 

·
Registered
Joined
·
259 Posts
Welcome to ACC! I sure do miss it and what you experience is normal. That is just how ACC works. I would never trust the car though 100%. Any car for that matter when coming up on one a bit close. Hover that foot over the brake pedal just in case. Not sure about the brake lights. I would imagine so since the car will brake automatically if you come up to close and fast using ACC. I always put the setting at the farthest. I always wanted more then enough distance while using the feature. We had it in our 2013 Honda Accord Touring. We really wanted the ACC feature with our 2LTZ. Problem is. It comes in a package with the 20" wheels. I did not want those and feel the 19's are perfect for this car. I also like the look and style of the 19's on the 2LTZ much better.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #6
Wow, has this problem gotten worse. Have just under 12K on the car and the problem continues to get worse. It's about due for it's second oil change so I am going to have them look at it. Of course, it won't do it while they have it! Yesterday we were cruising along and came upon a slower moving car. The adaptive cruise applied the brakes and made this sound very loud and jerked the car as if I had jammed on the brakes for a split second. Scared the sh*t out of me. I sure hope they can figure it out. I hate intermittent issues..
 

·
Registered
Joined
·
2 Posts
Wow, has this problem gotten worse. Have just under 12K on the car and the problem continues to get worse. It's about due for it's second oil change so I am going to have them look at it. Of course, it won't do it while they have it! Yesterday we were cruising along and came upon a slower moving car. The adaptive cruise applied the brakes and made this sound very loud and jerked the car as if I had jammed on the brakes for a split second. Scared the sh*t out of me. I sure hope they can figure it out. I hate intermittent issues..
Jonjonbear, I am having the exact same issue on my 2016 LTZ, and the same response from service that this is "normal." I have about 15,000 on mine now, and it is getting worse. I was told the ACC runs through the ABS (which that module is evidently in that front drivers side area). The vibration/grinding sound is annoying, but the hard braking is scary, and very disconcerting for my passengers and me. I contacted Chevrolet Consumer Hotline: 800-222-1020, and they have referred me to a new dealership, and are hopefully getting the regional folks and corporate engineers involved. For my next appointment, I am leaving my car (setting my trip odometer), and expecting them to drive around as if they own the car (for several days if needed), and use the ACC nearly all the time (I do use it a lot, even on non-highway roads, mainly so I don't speed). It's done it going on the downslope of a hill, or anytime the system senses the car needs to slow down and applies the brakes. Like yours, it's not consistent, but is happening nearly 65% of the time that the ACC "brakes", now (when the car was brand new, it happened like once a week at most). I am very frustrated. As I said, I use my cruise control a lot, and really do like the "adaptive" part of it. But, to me this is a safety issue...I can't have my passengers and objects thrown forward unexpectedly, and I am afraid a following-too-closely person is going to plow into me at 70 miles per hour one of these days. I hope "they" can get to the bottom of this anomaly, because it is not definitely NOT normal! Please post if you get any resolution for further information.
 

·
Registered
Joined
·
227 Posts
I don't have ACC, just the standard front collision warning system.

Do you see a lot of "false reactions" with ACC? I get a ton of those rapid beep warnings for no reason at all, even on the least-sensitive setting.

I would imagine a false reaction with ACC could be quite dangerous and cause a collision if your car jams on the brakes and someone is on the phone or otherwise not alert while following you.
 

·
Registered
Joined
·
479 Posts
ACC and our front collision use 2 completely different systems. ACC is radar based. Front collision is just a camera. If you are getting ALOT of false positives I would suggest cleaning the outside glass area where your rearview mirror is. I get a few here and there but not what I would describe as lots.
 

·
Registered
Joined
·
2 Posts
Mine is pretty sensitive...but it's not overly so. The ACC anomaly seems to be with its interaction with the ABS; a programming or relay timing issue. But, bignick2015, you are right...I have had it slam on the brakes numerous times (for only a 1 to 1.5 second "instant"), but it's jarring, and if I wasn't "holding the wheel," i.e., driving in a very relaxed posture, these brake-grabs could easily cause my hand to slip off the steering wheel and potentially cause me to lose control.

I didn't know the collision warning system used a different "system" to operate. See if what ICUBB suggests helps.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #11
I don't have ACC, just the standard front collision warning system.

Do you see a lot of "false reactions" with ACC? I get a ton of those rapid beep warnings for no reason at all, even on the least-sensitive setting.

I would imagine a false reaction with ACC could be quite dangerous and cause a collision if your car jams on the brakes and someone is on the phone or otherwise not alert while following you.
Hi BigNick, Don't really get false reactions with the ACC, except one situation it doesn't like. If you are traveling in the left lane and the car in front of you turns into a left turnout, the car will brake abruptly, I guess thinking because the car you were following is decelerating quickly and the car hadn't yet realized the car you were following is in a different lane. Other than that, it's pretty well behaved except this horrible grabbing/grinding sound I get ever so often. I'm not so sure that the ACC and anti collision system are totally separate on the cars with ACC, because the collision avoidance system uses the ACC to stop the car. The CA system will brake the car even with the ACC off, specially if you have the foot on the gas. I think if you have your foot on the gas, the car thinks you have not seen the impending threat. There have been a couple of instances, where someone pulled out across in front of me and the car started beeping and flashing and applied the brakes before I even had time to take my foot off the gas. Pretty amazing. Another thing it did that surprised me, we were on a two lane highway and on the opposing side was a pickup truck parked on the shoulder. There were two surveyors standing there and one of them stepped quickly about half way across the opposing lane and our car started beeping and flashing. I didn't realize the Impala could detect pedestrians. It's not done it since, perhaps it was something else.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #12
Jonjonbear, I am having the exact same issue on my 2016 LTZ, and the same response from service that this is "normal." I have about 15,000 on mine now, and it is getting worse. I was told the ACC runs through the ABS (which that module is evidently in that front drivers side area). The vibration/grinding sound is annoying, but the hard braking is scary, and very disconcerting for my passengers and me. I contacted Chevrolet Consumer Hotline: 800-222-1020, and they have referred me to a new dealership, and are hopefully getting the regional folks and corporate engineers involved. For my next appointment, I am leaving my car (setting my trip odometer), and expecting them to drive around as if they own the car (for several days if needed), and use the ACC nearly all the time (I do use it a lot, even on non-highway roads, mainly so I don't speed). It's done it going on the downslope of a hill, or anytime the system senses the car needs to slow down and applies the brakes. Like yours, it's not consistent, but is happening nearly 65% of the time that the ACC "brakes", now (when the car was brand new, it happened like once a week at most). I am very frustrated. As I said, I use my cruise control a lot, and really do like the "adaptive" part of it. But, to me this is a safety issue...I can't have my passengers and objects thrown forward unexpectedly, and I am afraid a following-too-closely person is going to plow into me at 70 miles per hour one of these days. I hope "they" can get to the bottom of this anomaly, because it is not definitely NOT normal! Please post if you get any resolution for further information.
Hi TX2, I am going to take the car in for it's second oil change on Monday and talk to them about it. Oddly, since it had that big event, it's only had one tiny one so the chance of it doing it for them if I left it, is unlikely. I am going to show them your post, and perhaps they can at least document it, and perhaps contact their corporate folks to see if they know something. Perhaps a software update would fix it. I'm at just a bit over 11K now.
 

·
Registered
Joined
·
27 Posts
mine does not do that, but ive used it like 3 times, and my lane beeping thing is turned off too since all it does is beep.

Now if i could figure out how to get the red brake flash on the windshild and beeps to stop i might like this car.... BEEEP BEEEEP BEEEP.. like 100 times a day
 

·
Registered
Joined
·
479 Posts
mine does not do that, but ive used it like 3 times, and my lane beeping thing is turned off too since all it does is beep.

Now if i could figure out how to get the red brake flash on the windshild and beeps to stop i might like this car.... BEEEP BEEEEP BEEEP.. like 100 times a day
Not sure if it exactly the same for models with the Adaptive Cruise Control as I do not have that option, but I do have Forward Collision Alert and that is the red flashing and beeping. To disable that click on the button shown in this picture until it turns to off. Again I don't know if you can turn it off on AAC models but worth a look.
 

Attachments

·
Registered
Joined
·
75 Posts
Discussion Starter #15
Nope. On the adaptive cruise models, you can't turn it off.

Not sure if it exactly the same for models with the Adaptive Cruise Control as I do not have that option, but I do have Forward Collision Alert and that is the red flashing and beeping. To disable that click on the button shown in this picture until it turns to off. Again I don't know if you can turn it off on AAC models but worth a look.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #16
Sounds like your driving habits! LOL!
Ours has almost 25K on it and the collision warning rarely goes on unless you approach a slow moving car too fast. I will say one thing, if something pulls out in front of you that sucker is on the brakes faster than you can get your foot off the gas..I read somewhere in a consumer report that they tested several cars automatic braking and put them in several classes as far as how effective it is, and the Impala is rated up there with the big boys in the top class (it should be for that price). The only time we have issues with the lane warning is when a road has a lot of those repair stripes that go along near the painted lines. Specially if the road is wet.

Cheers,

John


mine does not do that, but ive used it like 3 times, and my lane beeping thing is turned off too since all it does is beep.

Now if i could figure out how to get the red brake flash on the windshild and beeps to stop i might like this car.... BEEEP BEEEEP BEEEP.. like 100 times a day
 

·
Registered
Joined
·
27 Posts
its a good feature but seems to be to sensitive on suv or trucks.. your will going 35-45 truck or suv switch lanes with plenty of room.. BBBBEEEEEPPPP or if they are in the slow lane and turning into something, side road, gas station etc beeeppp... however on cars you can get real real close before it says anything... like omg we are going to crash before it warns you...


The brakes are very fast... i cant tell you how many time i dumped food and drinks with mine. I finally figured out what was doing it. Garage door goes up, i pull in, auto lights kick on and BAM brakes slammed on. I never figured what was causing it 100% but i moved the kids bikes, and a stainless steel work bench.. Im assuming the lights turn on reflect off the bike reflectors and lock up the brakes....

as for the lane beep, maybe its just this town, all the roads are old so the lines are faded real bad as well as the road being worn.. so your never dead center in the lane. it seems to work fine on the interstate, but in town its a joke.. maybe the sensor is to low or something. I can tell you the 16 denali has the same stuff and will actually steer you to keep you in between the lines, but it never goes off unless your on the line..

example, impala you can be say 3-4 feet from right side of the road yellow line, drive over to about 2 feet from line and BEEEEP. Denali doesnt beep or steer your back the other direction until your tires are about on the line... or say if there is a mail box, you will loose a mirror before the beep tells you are about to go off the road, where as the impala is like oh in a few feet you might be over the line.. only thing i can figure is height difference between the two..
 

·
Registered
Joined
·
1,273 Posts
I don't have the adaptive cruise but I do have the forward collision alert. At first it seemed ok but anymore it seems to go off for no reason. A few times I wasn't even behind a car and the damn thing just went off. They really need to work on that and makes me think if it was set up to apply the brakes it would really be bad. Ours it just sets off that loud beep and red light flashes and if cruise control is on it shuts it off.
Tried adjusting it to the presets and non eof them seemed to make it better. Probably a stupid question but I didn't see it in the manual explained. When you press the button on the steering wheel it cycles through the settings. Shows a car with 3 radar lines or 2 or 1 I believe. What are the settings for? Is the setting with 3 lines meant to alert you of cars farther away for higher speeds and the less lines is for city driving?
 

·
Registered
Joined
·
479 Posts
I don't have the adaptive cruise but I do have the forward collision alert. At first it seemed ok but anymore it seems to go off for no reason. A few times I wasn't even behind a car and the damn thing just went off. They really need to work on that and makes me think if it was set up to apply the brakes it would really be bad. Ours it just sets off that loud beep and red light flashes and if cruise control is on it shuts it off.
Tried adjusting it to the presets and non eof them seemed to make it better. Probably a stupid question but I didn't see it in the manual explained. When you press the button on the steering wheel it cycles through the settings. Shows a car with 3 radar lines or 2 or 1 I believe. What are the settings for? Is the setting with 3 lines meant to alert you of cars farther away for higher speeds and the less lines is for city driving?
Three lines means the it is reading at it's farthest distance, one line means alot closer before it would trigger. As far as applying the brakes this system has nothing to do with it. The auto-braking models have a form of radar added along with this.
 

·
Registered
Joined
·
1,273 Posts
Yea that's why I said mine doesn't auto apply the brakes because it only has forward collision alert. It would suck if it did because of the false readings.
 
1 - 20 of 23 Posts
Top