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Forward collision warning question

4K views 21 replies 11 participants last post by  Smoky 
#1 ·
Hello,
I got my new GC with adv tech package this week. Has anyone been able to verify FCW ? I set the sensevity to "far' and action to break, however the car never takes any action even if I am getting very close to the car in front while driving. ACC seems to be working though.
 
#2 ·
It will work Olivia. The most common way in which it is triggered is when you are driving behind another car (at just the right speed and distance) and the car in front makes a turn, out of your pathway. Should you fail to slow down, you'll get several warnings then the car will apply the brakes. Mine came to almost a complete stop during a voluntary testing.
 
#4 ·
The acc works great set your speed say 65 and off you go,someone pulls in front of you at 55 you slow down so then you pull out in the passing lane and back to 65.Try it out on the by-pass or turn pike.its a odd feeling at first

but the more you use it the more you'll like it.

fcw and acc are two diff. things
 
#5 ·
FCW will only trigger if it thinks a collision is imminent. It uses more than just speed and distance to judge that so it would be very dangerous to try and simulate it. FCW gets speed, brake state and wheel articulation from the ECM, relative speed between you and the front vehicle from the front Doppler Radar sensor and road posture from the front facing camera. it uses all this data to predict your risk during the next few seconds and will take progressive action if it thinks you are in danger. As f1anatic stated, FCW will sometimes false trigger while you negotiate a left bend and the vehicle in-front of you is making a right turn off the road. Though you know the turning vehicle is off the road, FCW still views it as a threat.
 
#6 ·
Guys,
Would that be right assumption that since acc is working the fcw should also work? I am a very defensive driver, therefore I don't think I will ever be able to figure out that this feature is working or not.
 
#7 ·
Yes with acc on it will apply the brakes if needed.one day a car in the passing lane jumped in front of me and then to the exit ramp.the brakes came on rather hard so too maintain the proper distance.
 
#8 · (Edited)
The late 2014 and all 2015 WK2s with ACC/FCW will actually brake the vehicle even ACC is not engaged.

The FCW (Forward Collision Warning should sound an audible alert and then, if no corrective action is taken, it should also apply the brakes. This should happen whether or not the ACC (Adaptive Cruise Control) is engaged.


"Testing" the FCW system is not advised since it would require almost colliding with another vehicle.
 
#9 · (Edited)
The late All 2014 and all 2015 WK2s with ACC/FCW will actually brake the vehicle even ACC is not engaged.

The FCW (Forward Collision Warning should sound an audible and visual alert, flashing the word "BRAKE" on the 7 inch screen behind the steering wheel and then, if no corrective action is taken, it should also apply the brakes. Brakes are applied as a series of "jolts" rather than a single, smooth but forceful braking instance. This should happen whether or not the ACC (Adaptive Cruise Control) is engaged.

"Testing" the FCW system is not advised since it would require almost colliding with another vehicle.
Edited for clarity.
I do not advise you to try it but it can be tested with relative safety. For liability reasons I will not describe how aside from the blurb above. Also, make sure that your FCW is set to FAR in the settings menu. Occasionally you may have to clean the radar lens as well as the windshield section in front of the camera lens: look to your rear view mirror from the outside of the vehicle. You should see a small triangular "window".
 
#13 ·
I have tried pulling up behind tractor trailer within a car length or less - nothing. ACC works great! 2 activations were round a curve with a car off the road - no braking, also one when approaching a car that was making a right turn. 2 "false" activations when no one in front for 100-150 feet. Drive close to car ahead and nothing happens!

Not sure if it is working or not!
 
#14 ·
The first day I got my ride, I was a bit "surprised" by this feature. I was on my way home from the dealer and as previously explained, a car in front of me turned onto a lane left of me and when I approached it, I heard an audible warning, got a message in the speedometer and after that, the vehicle applied the brakes on its own. Was a bit spooky...:lol:

I decided that the "far"-setting was a bit too sensitive for me so I set it to "close" (or "near" - not sure what it's called) and it seems that this setting is VERY tolerant. So far, it never came on - even when I tried to test it. I wasn't comfortable waiting any longer before braking on my own so I don't know when it comes on.

When I start my vehicle, I often get the message 'ACC/FCW limited functionality' but when I activate ACC, it's been working so far.
 
#15 ·
I have set it off by being in the right lane and merging into the left lane right behind a passing car. If you merge right on their butt (like your trying to sneak into a small gap) it will set off the warning. It helps if you are giving it some gas to match their speed.

If you really want to test it though I would try that with someone you know driving past you. You could easily piss the driver in front of you off.

Kind of like what I imagine a crashing plane to be like. screens blink and audible alarms beeping.
 
#16 · (Edited)
If you can't get an alert, you are not alone this system is flaky to say the least. If you want to test it safely try running into an inflatable object without touching the brake or letting off the accelerator and moving at over 5MPH. I used an air mattress with my 2015 overland with ACC+ Stop and FCW with stop. My ACC+ stop seems to work fine but the FCW+ stop does not work well at all, Chrysler and the dealer are no help at all.


I talked to Consumer Reports and they have not tested this feature on the JGC as the one they purchased did not have it but now plan to do it in the future. I have had the feature on a new Subaru and it worked perfectly as it should.
 
#17 ·
If you can't get an alert, you are not alone this system is flaky to say the least. If you want to test it safely try running into an inflatable object without touching the brake or letting off the accelerator and moving at over 5MPH. I used an air mattress with my 2015 overland with ACC+ Stop and FCW with stop. My ACC+ stop seems to work fine but the FCW+ stop does not work well at all, Chrysler and the dealer are no help at all.

I talked to Consumer Reports and they have not tested this feature on the JGC as the one they purchased did not have it but now plan to do it in the future. I have had the feature on a new Subaru and it worked perfectly as it should.
Works well on my 2014. Remember the fcw with mitigation is only going to beep and shutter and give you that mild braking if you are on the gas. The second you touch the brake and it knows now that your intention is to stop the jeep it will compensate with necessary hard braking if it feels you are not doing enough for the situation. That is how fcw with mitigation is designed to work. When you are on the gas the jeep doesnt know your intention in a situation maybe you would rather swerve quickly around something and if the jeep stood on the brakes in that situation well that may not be what you wanted so it needs that touching of the brakes to understand you and take more substantial action. There is a fine line between it doing what you want and being to intrusive.
 
#18 ·
I appreciate the thought but that just doesn't make a lot of sense. First you say it only works when your on the gas, then you need to touch the brake to so it understands your intention. If you touch the brake you disable the feature period.
The whole reason for having this feature is to alert you when you are not paying attention,falling asleep or in an emergency situation. If your touching the brake your in control and no alert is needed!
 
#19 · (Edited)
I think you are mixing up the FCW and the ACC, I only stated I was talking about the FCW in my last post, they are two different systems ACC is only on if you engage it and if you hit the brakes it turns off. FCW is always on as long as you have the box checked in the uconnect screen.

There are two parts to FCW with mitigation, the warning part and the mitigation part. With the warning part if you are on the gas and you are about to run into a car in front of you it will beep, shutter and give you some mild braking that's if you are on the gas if you stay on the gas you will run into that back of the car in front of you. However if you react at all to the situation and touch the brakes the mitigation part kicks in because now the jeep understands that its your intention to avoid a collision. The mitigation will brake hard if it sense you are not doing enough for the situation to slow the jeep, it will compensate with needed additional braking.

If you engage ACC(adaptive cruise control) while cruising it acts differently, by you engaging that system you are telling it to keep a set distance from the car in front of you if it needs to it will stand on the brakes to keep that distance to a stop, if you touch the brakes the ACC system disengages and turns manual control back over to you an in doing that its back over to the fcw with mitigation mode.

I have been using the systems for nearly two years now and I really do like them. FCW gives you that extra bit of warning and brake assistance with out being to intrusive and ACC is an excellent highway cruising tool.
 
#20 · (Edited)
While I am certainly glad to hear your satisfied with the safety features on your car and feel your FCW is working properly, many of us are not. That is because mine was not alerting at all under any circumstances. After they apparently did a re-flash it still is not working to these specs.


No, as I stated previously the ACC works great but they do work in conjunction by using the same cameras and sensors according to Chrysler. The following is a quote from the tech sheet they sent me:


" Forward Collision Warning Plus (FCW+) - The FFC in conjunction with the radar sensor is used to detect whether the vehicle is approaching another vehicle or large obstacle in its path too rapidly and will warn/assist the driver in avoiding/mitigating the incident (when Enabled). The driver has the ability to adjust the sensitivity and turn brake support on or off in the radio."
This means to me that I should get an alert any time that I'm in that situation otherwise it is malfunctioning! How else can you interrupt that!


Further they say and I quote:


"Adaptive Cruise Control and Forward Collision Warning Plus (ACC+/FCW+) - The FFC reports to the Adaptive Cruise Control (ACC) module to create the enhanced ACC+ as well as the FCW+ operation. These components share a private CAN C bus where data from the FCC is sent to the ACC module for data fusion."


This data goes on and on and gets even more detailed with the ACC/FCW Plus stop which is what my car has.
 
#21 · (Edited)
While I am certainly glad to hear your satisfied with the safety features on your car and feel your FCW is working properly, many of us are not. That is because mine was not alerting at all under any circumstances. After they apparently did a re-flash it still is not working to these specs.


No, as I stated previously the ACC works great but they do work in conjunction by using the same cameras and sensors according to Chrysler. The following is a quote from the tech sheet they sent me:


" Forward Collision Warning Plus (FCW+) - The FFC in conjunction with the radar sensor is used to detect whether the vehicle is approaching another vehicle or large obstacle in its path too rapidly and will warn/assist the driver in avoiding/mitigating the incident (when Enabled). The driver has the ability to adjust the sensitivity and turn brake support on or off in the radio."
This means to me that I should get an alert any time that I'm in that situation otherwise it is malfunctioning! How else can you interrupt that!


Further they say and I quote:


"Adaptive Cruise Control and Forward Collision Warning Plus (ACC+/FCW+) - The FFC reports to the Adaptive Cruise Control (ACC) module to create the enhanced ACC+ as well as the FCW+ operation. These components share a private CAN C bus where data from the FCC is sent to the ACC module for data fusion."


This data goes on and on and gets even more detailed with the ACC/FCW Plus stop which is what my car has.
I realize they share the same sensors and canbus when they are functioning I thought that was a given. it sounded in the post like you were confusing the two that's why I went on to explain them in trying to help, yes your system is broken. sorry for responding to your post to try and help I wont do it again
 
#22 ·
Hey, I appreciate all the help that I can get and many of the people on this forum do not fully understand the feature so by continuing this thread they can learn. I unfortunately now know way more then I ever wanted to and am still learning from yours and other posts. I'm afraid that they have dumbed the FCW down to the point of uselessness in later years because it was just giving them to many issues. I drove more than one 2015 at the dealer with the same result. The problem is they will not tell us that up front before we spend the big bucks. Now they can just say that it is working as it was designed and avoid dealing with it!
 
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