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Adaptive Cruise Control

12K views 22 replies 20 participants last post by  Ron35 
#1 ·
We just completed a 1700-mile journey in our 2019 Pacifica Limited and got to use the Adaptive Cruise Control (ACC). What a great feature. I have used standard Cruise Control on other cars. Problem is that on most highways there is just too much traffic to actually cruise at your desired speed without constantly having to manually decelerate or brake, and then push a button to resume. The ACC takes care of all that nicely. I went for hundreds of miles and never had to use my foot for braking or thumb on the steering wheel. Just let the ACC sensors determine when to slow down and resume to your desired speed. Really nice.

Overall the car ran really well and was a very comfortable ride for a long trip. Still happy with the purchase.
 
#2 · (Edited)
Do you experience any noise while using the ACC? I have 2019 Limited and when using ACC and the car needs to slow down it makes short strange noise (almost like metal grinding). No error codes light up it is just annoying. You can hear it over music if you pay attention but you would definitely hear it if you mute your radio. I know there was a separate thread which states it could be normal but nothing conclusive. What i find disturbing is that I reached out to FCA directly and they do not know if this is normal. I pinged several Chrysler services even in diff states and same thing. How is this possible? If it is by design, then every Pacifica with ACC should make this noise (supposedly actuator is making that noise) and FCA and their authorized services should know about it. Anybody else got a definitive answer?

If only some folks have that noise then the question is why and what is causing it and how to fix it?

If anybody wants to replicate it: if you engage ACC and it’s tracing the car in front of you and that car is going to a complete stop Paci will make that noise around 10 mph. On a freeway if you have ACC enabled let’s say at 60 mph and you are tracing a car in front of you, which is going 60 mph all you need to do is to override the ACC by stepping on a gas pedal to accelerate for a brief moment and then let go off of the gas pedal and (at least my) Paci makes that grinding noise as it slows it down to the get to the preset speed again. You can repeat it several times and you should get the noise every time.
 
#12 ·
Hi Nastominko,
We understand how this may be concerning. Although, I cannot determine if this is the normal operation of the vehicle since I am not mechanically trained. If you plan to return to your dealer for further diagnostic, I would be happy to get you connected with a Case Specialist to have this looked into further on our end. Please send us a private message if you'd like to discuss this further.

Lydia
Chrysler Social Care Specialist
 
#3 ·
ACC is greatly appreciated by me as I drive in Toronto, Ontario traffic up to Barrie, Ontario. As the original post stated, the Pacifica ACC does it all for you. In fact the only concern I have is when I do depress the brake and the ACC is then automatically disengaged. If you forget that you touched the brake and that the ACC is disengaged then you "think" erroneously the vehicle is going to slow your vehicle down... oops! In any case I love the ACC feature. The noise I believe the second poster is referencing is normal as the special motors are engaged to apply the brakes.
 
#4 ·
I haven’t noticed the noise mentioned by the other poster. Maybe I will have to pay more attention to the noises now. My only issue with adaptive cruise is the way the car speeds up when an obstructing vehicle in the front has cleared and set speed is higher than what it was going. In that situation the car accelerates like a teenage driver going on a rampage until it reaches the desired speed.
The designers who calibrated the adaptive cruise forgot that cruise control is activated mostly when drivers want a serene and relaxed driving experience.
 
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#5 ·
That sudden acceleration is a beef of mine too. When following a vehicle well under my ACC set speed, I pass by timing my lane change to a passing car on the left and hitch in behind them. The van locks on to that car but does not race like a teenager due to the gradual increase of spacing. Timing is critical for that manuver.

When a slower moving car suddenly exits and leaves open road ahead, I wish I had an answer.
 
#6 ·
I have tried the ACC several times in light highway traffic and on my commute (45mph roads). I have been less than impressed every time I have used it. None of them movements seem to be smooth, the braking is very late, and acceleration more than it needs to be. I engaged it one time with a car much further ahead in my lane, and the car slammed on the brakes and almost engaged ABS! The car was 100 yards ahead of me and traveling at speed.

At this point I have much less confidence the ACC system than I do my own driving...
 
#13 ·
The noise is the ABS pump that the ACC uses to stop the car. Normal I guess. I heard it on my previous SUVs with hill decent control, which also uses the ABS pump to control the brakes.
 
#16 ·
Really liked the ACC feature.
Like it most in within-city limits highway stop and go traffic. However there is one thing that could have been better. In my 2019 LTD, even with minimum car lengths, after complete stop car never accelerates on its own. I have to accelerate it manually, and then ACC does kick in (not like braking, where one manual brake stops ACC) as such not that big of trouble, but would be great if I don't have to accelerate it also.
 
#17 ·
Really liked the ACC feature.

Like it most in within-city limits highway stop and go traffic. However there is one thing that could have been better. In my 2019 LTD, even with minimum car lengths, after complete stop car never accelerates on its own. I have to accelerate it manually, and then ACC does kick in (not like braking, where one manual brake stops ACC) as such not that big of trouble, but would be great if I don't have to accelerate it also.
If it's stopped for less than two seconds (I think) it'll restart on its own, but not if it's stopped longer than that. However, you don't have to press the accelerator pedal, you can just press the "resume" button and it'll start accelerating itself.
 
#18 ·
Overall, I like the ACC. However, the rapid acceleration that occurs to get back up to cruise speeds (even at reasonable speeds) is very inefficient. I usually press "cancel" on the cruise control after the slow down to speed back up manually at a more efficient rate. The Chevy Volt (which is my other car) has a more gradual and efficient acceleration back up to cruise speed. Second, it is annoying when the ACC kicks in and slows you down after picking up traffic in the exit lanes unnecessarily.
 
#20 ·
I have a 2018 PacHy Limited and I love ACC! Coming from a few other vehicles with ACC, there's a few things to note. First, ACC is not perfect and not a self-driving system. As y'all have said, there are many times where the computer's algorithms just don't fully comprehend the driving situation at hand and as a result, improperly handle the driving dynamics. I'd argue that a majority of the time, the vehicle seems to do a surprisingly good job of reading the road and adapting accordingly, but I am always ready to take over if the I feel the vehicle isn't going to understand what's happening in front of me. Coming from 2 Honda vehicles with ACC, the Chrysler version is leaps and bounds better in my opinion. I feel it's less jerky than most other non-luxury ACC systems.

One thing to note about some of your experiences. There is a feature described in the manual called the ACC Overtake Aid. It's described as a feature designed to help you pass a slow-moving car in front of you. It is supposed to activate in situations where you are using ACC and a car in front of you is going less then your set speed, and then you put on your left blinker to pass them, the system will use an extra burst of speed to try and overtake the vehicle in front faster then the standard ACC acceleration. This doesn't describe everybody's situation, but it could explain some.

Finally, for the poster above who mentioned a metallic grinding noise that occurs for a short period of time at low speeds when slowing down. I had this issue too. To me, it sounded spot on like the brake pads. I noticed that it didn't happen all the time, and would frequently go away after I had been driving the car for a little while. I had been washing the car every week and using some spray on protectants on the wheels that I believe were getting onto the brake pads and rotors and causing the noise. As a test, I didn't wash or spray anything onto the tires for a month and the sound eventually stopped all together and never came back. It'll still come back after a fresh clean if I apply anything to the wheels again. I believe this is just part of how breaks work as I've heard a similar noise on other vehicles of mine as well when they were squeaky clean. I think it also may be more noticeable on this vehicle since it's so darn quiet when coming to a stop, especially with the PHEV version. This may not help you at all, but it just sounded like what I experienced when I purchased mine.

I appreciate all the discussion everyone!
 
#21 · (Edited)
Finally, for the poster above who mentioned a metallic grinding noise that occurs for a short period of time at low speeds when slowing down. I had this issue too. To me, it sounded spot on like the brake pads. I noticed that it didn't happen all the time, and would frequently go away after I had been driving the car for a little while. I had been washing the car every week and using some spray on protectants on the wheels that I believe were getting onto the brake pads and rotors and causing the noise. As a test, I didn't wash or spray anything onto the tires for a month and the sound eventually stopped all together and never came back. It'll still come back after a fresh clean if I apply anything to the wheels again. I believe this is just part of how breaks work as I've heard a similar noise on other vehicles of mine as well when they were squeaky clean. I think it also may be more noticeable on this vehicle since it's so darn quiet when coming to a stop, especially with the PHEV version. This may not help you at all, but it just sounded like what I experienced when I purchased mine.

I appreciate all the discussion everyone!
It happens at high speeds too. Basically every time ACC applies brakes. It has nothing to do with brake pads or getting water on them. It is somewhat poor design of the actuator and the pump used by ACC to brake.
 
#22 ·
Back to speed resuming too quickly . . . I quite using ACC on very first trip with my new (2019) Pacifica back in Dec. It worked great for slowing down behind slower vehicle, but then, when traffic cleared, and got into passing lane, it just "stepped" on it to get back up to speed. With all the electronics on these vans, they should make that adjustable. That's a pain to shut system off each time you pull out to pass someone! I'll just pay attention and slow down myself with decrease button on regulas cruise control.
 
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