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ChrisUCF99 04-16-2013 06:27 AM

Advanced Collision Warning Braking?
I traded in my 2012 Grand Cherokee Overland for a 2014 Overland. In my previous Overland I had the Advanced Technology Package with all the cool safety features as I do on my 2014.

I was driving down the road and a car ahead of me was turning, I was coming up on the car and did not break (as they would soon be out of my way).

The audible Advanced Collision Warning came on (which I was assuming it would, was kind of testing the feature out to make sure all was good in the 2014).

However I continued to NOT break when approaching the vehicle (they were almost turned). Typically when I'd hear that noise in the 2012 I would break. All of a sudden the Jeep started breaking for me. It was unexpected but kinda cool that it wouldn't allow me "crash" without putting up a fight.

Did the previous years do this, my 2012 never braked on my behalf, although I never gave it a chance to either.

bill_de 04-16-2013 06:51 AM

Re: Advanced Collision Warning Breaking?
Interesting. I read that the Jeep system in the 2014 did not apply the brakes in that situation.

Can't believe everything you read.


TitanFlyer 04-16-2013 06:55 AM

Re: Advanced Collision Warning Breaking?
I just talked to the service guys at Jeep yesterday about this as I wondered if it would brake for me when not in Adaptive Cruise Control mode. They tell me (and were quite sure of themselves) that it will NOT brake when not in ACC, and the Forward Accident Avoidance system will just warn you.

Now on the way home from the dealership I tested it and did what you did in your explanation, I came up on a car that was going into a turning lane and didn't brake at all, and the dash turned into a big BRAKE warning and the audible chime happened, but it didn't brake for me. I also tested the Adaptive Cruise on the highway and set it to 80 then pulled quickly into the slow lane while coming up on a car and it did brake for me.. nothing drastic but I could feel the car being hauled down to match speed of traffic in the slow lane.

So, are you sure you weren't in Cruise mode? I wonder if you have cruise on but not engaged if it does this? I thought I would love all this tech but honestly I am more afraid of it screwing me up than I am when driving a low tech vehicle like my wife's honda minivan.

bill_de 04-16-2013 07:23 AM

Re: Advanced Collision Warning Breaking?
I wonder if the OP mistook that last downshift, which will slow the car, as braking?


ChrisUCF99 04-16-2013 07:56 AM

Re: Advanced Collision Warning Breaking?
The Jeep definitely was breaking on its own, it even did it in kind of like an anti-lock brake mode where it pumped the breaks several times so as to not lock up the wheels etc.

I was not in cruise control mode either. It was unexpected so I thought I'd mention it on here as that never happened in my 2012. Wasn't sure if it was a "feature". The warning has gone off before and NOT applied any brakes for me, but before the warning was short lived or I was already applying the breaks.

This time the warning was audible for two seconds or so (so a considerable amount of heads up), I didn't apply the breaks at all and as I got closer to the car ahead of me, there was like 3 hard pumps on the brakes and I had a wtf look on my face, but then was thinking that it was a nice safety feature.

655321 04-16-2013 09:55 AM

Re: Advanced Collision Warning Breaking?
I can confirm that on 2 separate occasions my overland with tech applied the brakes to avoid collision. I had a guy make a U turn in front of me while on a 2 lane highway, BRAKE lit up in red on the center dash and the vehicle applied hard brake pressure. The next instance was looking for some sunglasses in the seat next to me, the car in front of me slammed on its brakes , FCS went off and applied brakes again.

TitanFlyer 04-16-2013 10:05 AM

Re: Advanced Collision Warning Breaking?
Wow.. guess they are wrong... I would think that would be the way it should work, but it would be incredibly tough for the computer to figure out when a real accident is going to happen. I would also think that if it went off when it really wasn't an accident possibility and applied "hard braking" that it may actually cause a real accident.

I think tech may be getting a little intrusive...I notice after only a couple days with my truck that I rely on blind spot warning way too much now. I still check but its probably giving me too much confidence that nobody is there.

2012 Summit 04-16-2013 10:08 AM

Re: Advanced Collision Warning Breaking?
From the 2014 Owners Manual:


Forward Collision Warning (FCW) With Mitigation
The Forward Collision Warning (FCW) system with
mitigation provides the driver with audible warnings,
visual warnings (within the EVIC), and may apply a
brake jerk to warn the driver when it detects a potential
frontal collision. The warnings and limited braking are
intended to provide the driver with enough time to react,
avoid or mitigate the potential collision.
NOTE: FCW monitors the information from the forward
looking sensors as well as the Electronic Brake Controller
(EBC), to calculate the probability of a forward collision.
When the system determines that a forward collision is
probable, the driver will be provided with audible and
visual warnings and may provide a brake jerk warning.

If the driver does not take action based upon these
progressive warnings, then the system will provide a
limited level of autonomous braking to help slow the
vehicle and mitigate the potential forward collision. If the
driver reacts to the warnings by braking and the system
determines that the driver intends to avoid the collision
by braking but has not applied sufficient brake force, the
system will compensate and provide additional brake
force as required.

When the system determines a collision with the vehicle
in front of you is no longer probable, the warning
message will be deactivated.

TitanFlyer 04-16-2013 10:19 AM

Re: Advanced Collision Warning Breaking?
Just looked at my Window Sticker and it does say "with Mitigation and Advanced Braking Assist" so I guess I was just not understanding what that meant.

I will say that when the collision warning went off, it basically was too late for me to brake enough to stop from hitting them anyway... but I am sure the computer is smarter and faster than me.

Specx 04-16-2013 10:20 AM

Re: Advanced Collision Warning Breaking?
I've had the same happen and it does apply the brakes. There's an option in the Uconnect settings to enable/disable braking when FCW is activated. I think I read somewhere it will only apply 40% braking force and you will need to get involved to bring the vehicle to a complete stop. It's a good system and a feature I can see helping a collision, but it has gotten in my way when I'm aggressively trying to get around someone on the freeway and it applies the brakes in the middle of a lane change.

Temerarius 04-16-2013 11:40 AM

Re: Advanced Collision Warning Breaking?
While test driving an Overland with the Advanced Tech Group I had some yahoo cut across 3 lanes to get in the lane on the far side of me. He came within probably 6 feet of the Jeep in doing so and the Jeep (in Cruise) not only sounded the alarm but seemed to dynamite the brakes at the same time.

Whatever system or combo of systems it's using, I really enjoy having that extra set of "eyes" there for me.

Snipe315 04-16-2013 02:34 PM

Re: Advanced Collision Warning Breaking?

This is a NEW feature in the 2014s.

My 2012 Overland with ACC and FCW will not apply the brakes unless the ACC is also activated. The FCW will only provide an audible and visual warning to a possible pending collision.

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