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-   -   Forward Collision Warning System Issues (http://www.jeepgarage.org/f107/forward-collision-warning-system-issues-24376.html)

Kodiak 06-13-2011 04:20 PM

Forward Collision Warning System Issues
 
Just purchased a 2011 Overland 5.7L fully loaded (May 2011). Very happy with everything except the darn FCW systems. Also noted a minor issue with the 730N RHR media system. I've reported this to Jeep and hopefully will have a response soon.

Forward collision warning system

1. It doesn't work with moving vehicles; doesn't detect objects when switching lanes
2. Far vs Near setting doesn't seem to matter

I've tested this functionality on mine and also a few brand new Overlands at the dealership and they all behave the same. You can ride up really fast on the tail of a car and no alarm will sound. If the car in front is stopped or nearly so, the "Brake" alarm will sound when you reach close to 10-15 feet (not exactly an avoidance distance! :) ) If the vehicle in front begins to move forward and you continue to approach, no alarm will sound.

In addition to what limited information is provided in the Jeep marketing material and also federal guidelines for these systems, the Jeep system doesn't seem to conform.

I think this is a serious issue and have communicated the same to Chrysler Jeep. They seem to be on it, but haven't received a resposne yet.

2. 730 Media Center won't update all my iphone 4 address book records (I have over a thousand...I know a lot). Stops at 848 records.

3. 730 Media Center - received an error message yesterday after parking in an underground garage for 5 hours stating that it couldn't find the Nav database and was in the process of installing. Took me 15 mins to get home and the Nav/Voice Recognition functionality refused to function. If you looked up the System information on the main menu, it read "error" next to the database version. There was an icon showing that records were being transferred next to the bluetooth icon...similar to when you update your address book. The next morning the system was back to normal. Does anyone know if you can reset the Nav system somehow?

Looking forward to your responses!

ColdCase 06-13-2011 05:23 PM

Re: Forward Collision Warning System Issues
 
My FCW system seems to work OK, has alerted me quite a few times when cars ahead were moving at a different rate than I was, and depending on the rate the alert distance varies. It also has alerted me on a lane change when just crossing into the lane when I was close to the car ahead. I think it may not work well vs stationary objects, although I may have chickened out before the alarm. The alarm will not sound if you are braking, it will sound when the ACC is braking, however. I don't think I would depend on the system in a fog. Were you looking at vehicles with early build dates by chance?

The only problem I've had with the 730 RHR is that it keeps forgetting where home is... and the directions it provides are a cut below a Garmin unit. I don't use it with an iPhone, however.

jcnaranjo 06-13-2011 06:05 PM

Quote:

Originally Posted by Kodiak (Post 430146)
Just purchased a 2011 Overland 5.7L fully loaded (May 2011). Very happy with everything except the darn FCW systems. Also noted a minor issue with the 730N RHR media system. I've reported this to Jeep and hopefully will have a response soon.

Forward collision warning system

1. It doesn't work with moving vehicles; doesn't detect objects when switching lanes
2. Far vs Near setting doesn't seem to matter

I've tested this functionality on mine and also a few brand new Overlands at the dealership and they all behave the same. You can ride up really fast on the tail of a car and no alarm will sound. If the car in front is stopped or nearly so, the "Brake" alarm will sound when you reach close to 10-15 feet (not exactly an avoidance distance! :) ) If the vehicle in front begins to move forward and you continue to approach, no alarm will sound.



Looking forward to your responses!

The previous post hit the nail on the head. If you are pressing the brake pedal, FCW will not activate. I think it assumes you are takin appropriate action.

Kodiak 06-15-2011 04:52 PM

Re: Forward Collision Warning System Issues
 
Thanks for responding guys! In response to your question, my Overland was manufactured in May,2011.

I've tried accelerating rapidly without hitting the breaks while following behind a car, and it doesn't work. When I reported this to the dealership, we tested it out on a fully loaded Overland, just like mine (except for the missing chrome package :-)) and they all seem to have the same issue.

Additionally, the alarm only triggers on my vehicle when you're too close to the vehicle - in the case of a stopped vehicle, that is...way too late to brake if you're not prepared for it.

Have you tried accelerating behind a car in front to see if it works? How far away are you when the alarm sounds? I assume it'll vary with speed, but generally speaking....would someone who, as an example, falls asleep at the wheel be able to brake before a collision? It doesn't seem to be following the specs (which aren't very detailed with regard to Jeep, but the federal standards are pretty darn clear).

ColdCase 06-16-2011 08:53 AM

Re: Forward Collision Warning System Issues
 
I have accelerated during a lane change and when the sensor picked up the slower moving car in the second lane, the alarm sounded, with plenty of margin.

Perhaps the tall GC hood or your riding position is giving you an impression that you are closer to the car in front than you realy are?

bpmcgee 06-16-2011 09:38 AM

Re: Forward Collision Warning System Issues
 
Another note -- the far vs. near mode is ONLY for the ACC, not the FCW -- they use the same sensor, but are different systems.

In my experience, it seems like the FCW works as follows -- it uses the sensor to measure the rate of closure to the vehicle in front of me and the distance. Remember if you multiply the inverse of the rate (in seconds/foot) by the distance (feet) you get seconds. If that number, which represents the seconds to collision, is LESS than a fixed amount, the alarm sounds.

In other words, the greater the closure rate the earlier the alarm will sound. In practice I've heard it sound (at a guess) at about 2 car lengths or less.

B

Kodiak 06-16-2011 06:35 PM

Re: Forward Collision Warning System Issues
 
Quote:

Originally Posted by ColdCase (Post 431908)
I have accelerated during a lane change and when the sensor picked up the slower moving car in the second lane, the alarm sounded, with plenty of margin.

Perhaps the tall GC hood or your riding position is giving you an impression that you are closer to the car in front than you realy are?

Are you sure it wasn't related to a car in you blind spot? This also gives off a sound. The alarm should sound and a warning suggesting that you should "Brake" appears in the dashboard. I've only been able to reproduce this sound at a traffic light with a stopped car and also accelerating toward a large road repair cone...both stationnary objects. Thanks for responding ColdCase. If you can try it out one of these days, I'd love to know if you can get it to sound an approaching a moving vehicle (obviously use caution as to not have a rear-end collision!!)

Kodiak 06-16-2011 06:38 PM

Re: Forward Collision Warning System Issues
 
Quote:

Originally Posted by bpmcgee (Post 431926)
Another note -- the far vs. near mode is ONLY for the ACC, not the FCW -- they use the same sensor, but are different systems.

In my experience, it seems like the FCW works as follows -- it uses the sensor to measure the rate of closure to the vehicle in front of me and the distance. Remember if you multiply the inverse of the rate (in seconds/foot) by the distance (feet) you get seconds. If that number, which represents the seconds to collision, is LESS than a fixed amount, the alarm sounds.

In other words, the greater the closure rate the earlier the alarm will sound. In practice I've heard it sound (at a guess) at about 2 car lengths or less.

B

bpmcgee, thanks for your response too. The Near/Far setting in the system setup is actually related to the FCW...if you check it again you'll see that it's a subselection to the FCW menu item.

Would love for you to validate that you can replicate too...I'm almost certain that they've gotten the logic wrong....2 car lengths may not be enough, in my opinion, for a distracted driver. Granted, no responsible person should ever have to use this technology, but I'm just keen to ensure it's working the way it should...out of principle. Else, no complaints with the Jeep...it's a fine machine!

ColdCase 06-17-2011 09:03 AM

Re: Forward Collision Warning System Issues
 
Quote:

Originally Posted by Kodiak (Post 432220)
Are you sure it wasn't related to a car in you blind spot? This also gives off a sound. The alarm should sound and a warning suggesting that you should "Brake" appears in the dashboard. I've only been able to reproduce this sound at a traffic light with a stopped car and also accelerating toward a large road repair cone...both stationnary objects. Thanks for responding ColdCase. If you can try it out one of these days, I'd love to know if you can get it to sound an approaching a moving vehicle (obviously use caution as to not have a rear-end collision!!)


I am absolutely sure, brake visual and audible warnings showed up, again on the way to work this AM. I have the side collision warning tone turned off. The triangle was off.

I have also merged into a highway and while checking the mirrors for oncoming trafic, the cars ahead were slowing down.. alarm was plenty soon enough to avoid a rear ender.

Again as I and others have stated before, my alarm has sounded several times coming up on moving vehicles including recently a motorcycle that moved into my lane. The warning distance seems to be directly related to MPH and the closing speed. If you are a very conservative driver, the warning distance may seem too short to you, but I think its perfect for me. Two car lengths is a lot at 40 mph. I would turn the warning off instead of dealing with false alarms. I have a spouse to constantly reminding me of following too close, don't also need the JGC telling me :) I have my ACC distance set at minimum.

I have not had enough confidence to try it on a stationary object.

In my opinion, distracted drivers should get off the road.

bpmcgee 06-17-2011 02:11 PM

Re: Forward Collision Warning System Issues
 
Quote:

Originally Posted by Kodiak (Post 432224)
bpmcgee, thanks for your response too. The Near/Far setting in the system setup is actually related to the FCW...if you check it again you'll see that it's a subselection to the FCW menu item.

Would love for you to validate that you can replicate too...I'm almost certain that they've gotten the logic wrong....2 car lengths may not be enough, in my opinion, for a distracted driver. Granted, no responsible person should ever have to use this technology, but I'm just keen to ensure it's working the way it should...out of principle. Else, no complaints with the Jeep...it's a fine machine!

Kodiak -- in re 2 car lengths -- I'm not sure EXACTLY how far it was -- I'm guessing about 1-2 second collision time. Obviously they can't extend that too far, or it would be going off any time you overtake someone.

B

kaflyboy 06-17-2011 03:50 PM

Is there an audible noise when there is a car in your blind-spot? I have not noticed that feature.

jcnaranjo 06-17-2011 07:38 PM

Quote:

Originally Posted by kaflyboy (Post 432770)
Is there an audible noise when there is a car in your blind-spot? I have not noticed that feature.

If all of the settings are ON in the EVIC, then it will sound when there is a car in your blind-spot AND you activate the turn signal for that side...


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