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Discussion Starter · #1 ·
When I set the cruise (ICC) at say, 50 MPH and the vehicle is traveling downhill for a stretch of 1 mile, the speed keeps increasing beyond 50 MPH (with the display blinking). The regular cruise I had on my 08 Honda CR-V and even my 98 Civic used to maintain the speed in downhills by slightly applying brakes. When Infiniti calls this Intelligent Cruise, why is this so stupid?
Anyway to change this somewhere in the settings so that it will act a little sane?
 

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This is not right. My commute has a big hill, regardless I'm using ICC or not, the speed is always stable when I'm going down hill. The rpm, however, increase when down hill to use engine brake to maintain the speed. Take it to the dealer.
 

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Hi Kravyshank. :)

It really depends on the downhill slope you are travelling & the speed you are doing. I live in a mountainous high altitude location with various hills of many shapes & steepness. My experience with cruise controls of various designs is that on incline or decline, they will have issues & not be to our expectation. It's not the same consistency as what you'll get driving in relatively flat highways.

There are just 2 situation I simply turn-off the cruise control. 1) Driving in the snow 2) Encountering major uphill/downhill situations.

At certain steep angle, even reasonable automatic downshifting to employ engine brake will not be consistent or even reliable to maintain constant speed going down - if programmed on higher speeds, and while on steeper downhill. Carrying load affects this too.

On a decline of 6% while doing 45 mph; I found that the lowest CVT downshift range in the JX35 is down to the equivalent of 3 or 4 range, but it would not do less than this. I am not sure if the ICC would even engage the brakes. It did one time, but not because of the downhill speed, but because it "sensed" a slower car located downhill ahead of mine.

My experience is the same as yours that the system will simply allow an overshoot beyond programmed speed & indicate a blinking velocity on the dash. However, in fairness, this only happens in steep downhill on a full heavier load at higher speeds.

At lighter loads, travelling on a much benign slope, and with lowered programmed speed (< 45 mph)... it still performs as expected.
 

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The G and a couple rental 300M maintained set speed of 85 going up and down the huge I15 slope to/from Vegas. A Venza did poor on declines though and did not maintain set speed, kept on increasing. I guess every car is different...annoying.
 

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Discussion Starter · #5 ·
Hi Kravyshank. :)

It really depends on the downhill slope you are travelling & the speed you are doing. I live in a mountainous high altitude location with various hills of many shapes & steepness. My experience with cruise controls of various designs is that on incline or decline, they will have issues & not be to our expectation. It's not the same consistency as what you'll get driving in relatively flat highways.

There are just 2 situation I simply turn-off the cruise control. 1) Driving in the snow 2) Encountering major uphill/downhill situations.

At certain steep angle, even reasonable automatic downshifting to employ engine brake will not be consistent or even reliable to maintain constant speed going down - if programmed on higher speeds, and while on steeper downhill. Carrying load affects this too.

On a decline of 6% while doing 45 mph; I found that the lowest CVT downshift range in the JX35 is down to the equivalent of 3 or 4 range, but it would not do less than this. I am not sure if the ICC would even engage the brakes. It did one time, but not because of the downhill speed, but because it "sensed" a slower car located downhill ahead of mine.

My experience is the same as yours that the system will simply allow an overshoot beyond programmed speed & indicate a blinking velocity on the dash. However, in fairness, this only happens in steep downhill on a full heavier load at higher speeds.

At lighter loads, travelling on a much benign slope, and with lowered programmed speed (< 45 mph)... it still performs as expected.
Thanks for your response. I agree, the speed does not overshoot by much if the cruise is set for < 45 mph. However, when we go on long road trips, we would set it at about 65 MPH on highways and it doesn't make sense if it runs at 73 MPH just because there is a downhill. Downhill stretches of half a mile are very common on interstates.
 

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I live in a populated city. Cruise control is not a feature I even can use. Stop and GO traffic all day everyday.
 

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My experience with the ICC is that it speeds up much faster than any other car I have owned in the last 30 years. This speed gain is not under a heavy load condition and it does it on ANY downgrade. Of course it is worse on steeper hills. What is more unusual is, if the ICC is not engaged, the car speeds up less quickly than when under the car's "control." JX drivers are going to be getting ticketed by law enforcement who tend to wait at the bottom of hills if they are not paying strict attention to the car's speed. Which, IMHO, totally defeats the purpose of having ICC in the first place. The fact that the very small numbers indicating the set speed BLINK when the set speed is exceeded is a very subtle warning and easy to overlook in the sea of information displayed in front of the driver. The car can maintain a set speed with great accuracy down any hill when there is a car in front of it, and can even bring the vehicle to a compete stop safely if the car in front also stops. It seems the engineers forgot that, on occasion, there is no car to follow. But that does not mean the car should go as fast as gravity can accelerate it downhill and make absolutely no attempt to slow itself using either brakes or transmission. There is a video posted on YouTube of a Nissan Altima owner demonstrating how that car, also equipped with a CVT, is capable of holding a set speed within a few MPH on a mountain road without a problem. The video clearly shows the tach increasing as the CVT induces engine compression to control vehicle speed.
I just do not understand how a vehicle such as the new JX can be so advanced in some areas, yet manifest a potentially dangerous "bug" in the system which could lead to speeding citations at best, and totally avoidable accidents at worst when through distraction, darkness or fog, a driver cannot discern the speed build-up until a turn is encountered and the car's increased speed makes maneuvering through it "problematic."
Instead of making excuses and pointing out the language in the owner's manual stating that when the ICC causes the car to speed up to an unacceptable degree, it should be turned off. The device is call an INTEGRATED CRUISE CONTROL, meaning it is integrating the transmission AND braking systems to CONTROL vehicle speed. It does not do this in a competent manner and represents an EPIC FAIL of this important vehicle control system.
It is my fervent hope that Infiniti will stop putting their energies into defending the indefensible and devote themselves to fixing the problem. That a Nissan can deal with this driving scenario and an Infiniti is incapable of doing the same thing should make it obvious that it is an UNACCEPTABLE situation that needs to be addressed and corrected on all JXs in service ASAP.
 

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I donot understand what youa re talking about, If you engage the ICC, it will either slow down in heavey traffic following a slow car, even to a complete stop, or goes at the set speed, even down hill. And yes, when you go down hill, the engine speed up to engage engine brake to maitain the set speed, just as the Altima you described. If you JX doesnot control teh speed in ICC when going down hill, take it to your dealer.
 

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Not a huge trust factor between me and the ICC. Maybe I'm just old school :D

But I've always noticed that on cruise control when going downhill alot of cars get confused. I know my Acura does.
 

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The car has been to the dealer and the ICC has been REPLACED.
The car gains more speed going downhill than any vehicle I have driven in the past two or three decades.
If you apply the brakes, the ICC turns off, which is fine. But the ICC should be able to CONTROL the speed on its own.That is its FUNCTION.
 

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With all due respect, if you do not own a JX, or at the very least have not driven it under the circumstances under discussion, you are really not qualified to comment on its driving characteristics.
The point that is trying to be made is that the JX responds differently than any other Infiniti when going down a hill of any appreciable grade with the ICC engaged and there is not another vehicle to follow.
I was probably not clear enough that MY comment is specifically about the JX model.
 

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The car has been to the dealer and the ICC has been REPLACED.
The car gains more speed going downhill than any vehicle I have driven in the past two or three decades.
If you apply the brakes, the ICC turns off, which is fine. But the ICC should be able to CONTROL the speed on its own.That is its FUNCTION.
Does it now function correctly as expected?
 

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NO.
Unfortunately, the problem is inherent in ALL JX series cars. The new ICC module allows an unacceptable speed gain, the same as the original.
 

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If it is a short downslope, mine slows too, as the ICC interprets the bottom of the hill as another car.
But on a hill of any distance, unless it is a very slight slope IF THERE IS NO VEHICLE IN FRONT OF IT, it speeds up. This is the case with the CVT in any of its modes.
 

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NO.
Unfortunately, the problem is inherent in ALL JX series cars. The new ICC module allows an unacceptable speed gain, the same as the original.
Sorry to hear that. My commute has a large hill and I tried it again today, no problem. Set at 65 and at at teh bottom of the hill, it is still 65, with no var in front, just as it supposed to be. I had a Maruno with regular cruise, it maintians the speed downhill too.
 
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