Cruise Control and Curves

[CamarilloBrillo]

I have a new 2012 4.6 With Tech and Premium and just took it on my first trip (which rolled it over 1000 miles).

I'm still getting used to it's quirks such as the Surround Sound setting, seat memory and such but one thing I just can't overlook is the Smart Cruise Control and it dropping speed around curves.

I noticed that, unpredictably, it would drop 15 MPH from 75 to 60 pretty quickly when I went around curves on an interstate highway (US 77 = WV Turnpike). At first I thought it was picking up the guardrail but I then eliminated that because it a) never showed a second car on the display and b) it did it when there was none. If I were the car next to me I would be cursing at the idiot who couldn't maintain speed. It's really, really annoying.

I can't tell if it's the cruise control or if somehow the car get an erroneous reading around curves (some but not all) and thinks it's going faster than it is. I don't think it's the latter since I have noticed the car breaking when it went too fast down hill but it never breaks around curves - just lets off of the throttle and then guns it when the road straighten outs. I only takes a second or 2 to get the 15 MPG back but, to the drivers next to me, it must look like I stomped the gas after freaking out about a moderate curve.

Any ideas would be helpful. Could it be the ESC? I really need to figure this out or just stop using the cruise control on similar roads. Sad, because my Toyota Sequoia takes that road like a champ and it's top heavy.

ETA: There were no cars nearby so it wasn't tracking adjacent cars.

 

[Mark_888]

I think you mean MPH, not MPG. It sounds like either Smart Cruise Control wants you to slow down around corners, or it needs service. I am fairly sure it doesn't happen on regular cruise control (not Smart version) and is not related to ESC.

 

[CamarilloBrillo]

I think you mean MPH, not MPG. It sounds like either Smart Cruise Control wants you to slow down around corners, or it needs service. I am fairly sure it doesn't happen on regular cruise control (not Smart version) and is not related to ESC.

I did mean MPH thanks so much.

I assume, from your post, you have "regular" cruise control and that it doesn't reduce speed?

 

[Mark_888]

I assume, from your post, you have "regular" cruise control and that it doesn't reduce speed?

That is correct.

 

[DeeVa]

It is a fence or guardrail. I have tested this and found that to be the issue (even though I swore on another thread that there was no fence or guardrail when this happened).

 

[Rey]

The "adaptive" cruise control will "see" a lane barrier or other obstruction on a curve and slow the car. At this time it appears there is no filter for this problem. The answer is to disconnect/cancel cruise control on any curvy section. Just hit the "resume" when you are once again on a comparatively straight section.

 

[CamarilloBrillo]

It is a fence or guardrail. I have tested this and found that to be the issue (even though I swore on another thread that there was no fence or guardrail when this happened).

The "adaptive" cruise control will "see" a lane barrier or other obstruction on a curve and slow the car. At this time it appears there is no filter for this problem. The answer is to disconnect/cancel cruise control on any curvy section. Just hit the "resume" when you are once again on a comparatively straight section.

I appreciate the responses but this is happening when there is no barrier - on open 4 lane roads - open to the right and to the left. Also, if this is the case shouldn't I see the "car" in the console? Unless it's specifically designed to behave differently it doesn't behave as if it detects a car. I would expect it to freak out more and hit the brake which it never does in this situation. I am going to take it to service and ask them but considering the response I received about the ECO setting I'm not holding onto much hope that they will be able to help. I'm also going to ask them if they have any idea about a terrible melting plastic smell I detected on the trip - I'm hoping that's a normal brake smell but doubtful.

 

[BacktoHyundaibychoice]

I appreciate the responses but this is happening when there is no barrier - on open 4 lane roads - open to the right and to the left. Also, if this is the case shouldn't I see the "car" in the console? Unless it's specifically designed to behave differently it doesn't behave as if it detects a car. I would expect it to freak out more and hit the brake which it never does in this situation. I am going to take it to service and ask them but considering the response I received about the ECO setting I'm not holding onto much hope that they will be able to help. I'm also going to ask them if they have any idea about a terrible melting plastic smell I detected on the trip - I'm hoping that's a normal brake smell but doubtful.

Mine has never slowed on a curve or by seeing a guard rail. One of us has a sensor that's broken.

 

[DeeVa]

Mine has never slowed on a curve or by seeing a guard rail. One of us has a sensor that's broken.

That would be you! Or perhaps this is a 2012 vs. earlier model issue. As far as the car icon, it only illuminates when it brakes for the first time. If you don't see it when it initially applies the brakes, then it doesn't illuminate as it continues to brake. I often will set a high speed and just let adaptive cruise and traffic congestion drive me into work. I am going under my set speed the entire time, but the brakes aren't illuminated on the panel icon.

 

[BacktoHyundaibychoice]

That would be you! Or perhaps this is a 2012 vs. earlier model issue. As far as the car icon, it only illuminates when it brakes for the first time. If you don't see it when it initially applies the brakes, then it doesn't illuminate as it continues to brake. I often will set a high speed and just let adaptive cruise and traffic congestion drive me into work. I am going under my set speed the entire time, but the brakes aren't illuminated on the panel icon.

And last year I drove 2 2500 mile trips from Chicago to Orlando and back, and the only time the brake lights illuminated in the display was when the brakes were applied. Other slowing was engine braking and the lights didn't come on, as it should be.
As for the car icon, it's always on when it's in range of my sensor, lights or no lights, with no lights AND a car icon indicating engine braking.
For the record, mine is a 2011. And I suspect it's working perfectly.

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[CamarilloBrillo]

That would be you! Or perhaps this is a 2012 vs. earlier model issue. As far as the car icon, it only illuminates when it brakes for the first time. If you don't see it when it initially applies the brakes, then it doesn't illuminate as it continues to brake. I often will set a high speed and just let adaptive cruise and traffic congestion drive me into work. I am going under my set speed the entire time, but the brakes aren't illuminated on the panel icon.

Mine behaves differently I think. When the road is clear ahead of me there is no second car icon. When a car is detected the second car shows up and my car slows by reducing throttle. If the distance is too short then the car brakes and my car icon on the dash has brake lights that light up. When the road clears again the second car icon disappears.

I, too, have set a max speed and never touched the gas or the brake for many miles and it works flawlessly ... so far. It will even slow the car to nearly stopping and resume as long as I don't have to hit the brake to come to a complete stop. Car pulling into traffic close to be causes the car to freak and brake which I don't care for but at least it's doing it's job. I try to deal with that type of traffic by switching distances.

The service rep at the dealership called the technician and they never heard of it but he suggested that maybe the speed on the wheels where being read at different speeds and the ESC might be slowing the car down.

 

[Shawn33]

I believe the second car is just an indicator that the systems "sees" something up ahead. I've been travelling and get the second car and then change lanes to the left and the car goes away and my speed never changes. If I can't move over the car will reduce throttle as the following distance is neared. On some smaller 2 lane roads I will use it more when following a car then when there is no traffic. With a car in front of me I let him do the slowing for curves and such and just follow at a fixed interval. I think people get a little wierded out by it because the following distance doesn't really change. In that scenario I use the middle or longer distance. On the freeway the short distance is still too long in a lot of situation.

A work around for the original OP until his CC gets fixed would be to step lightly on the gas around the curve which will override the smart cruise.

Shawn

 

[genedy]

I just had this happen to me on Sunday on a trip to Lake Tahoe. Going around a slightly tight turn, I noticed that the car would slow down about 5mph going around a turn. I can't decide if it's the ESC kicking in, or the sensors. I haven't had it happen outside of this trip.

On rare occasion, I've had the sensors pick up a car next to me/infront and slow down.

 

[hwks1]

Mine does this and seems perfectly normal. There are vehicle dynamics controls on the car. I presume it senses the lateral forces on the curve and slows you down.

 

[CamarilloBrillo]

Mine does this and seems perfectly normal. There are vehicle dynamics controls on the car. I presume it senses the lateral forces on the curve and slows you down.

Obviously we have different driving styles as I would set my my Toyota Sequoia at 75 and leave it there except for 2 curves however my Genesis slowed down from 75 to 60 on dozens of curves. It felt ... well ... afraid. Afraid to take the same curve as my Sequoia with no problems.

That's not cool and it's extremely annoying to me, the driver, and I can't imagine how it must look to the cars around me - look at that old fart who can't take a tiny curve at the speed limit.

 

[jnc2000]

Experincing the same thing here on my daily commute between OH and PA.

The "smart" cruise control really doesn't like curves with guard rails... nor does she enjoy curves on highways with more then 3 lanes. The system can get confused with traffic on I79, I76 I80, I376, [etc] (Airport area round Pittsburgh). Another thing I noticed is it'll engine brake / drop a gear when going over expansion joints, railroad tracks, or other imperfections in the road.

Just got my "survey" last night and I gave a piece of my mind regarding this matter and some other things...

 

[littlecf]

I have a 2011 4.6, and I've noticed this with my car, too, although I don't think I've seen a 15 mph decrease. In my experience, it varies depending on the severity of the curve, but the most I've noticed is about 10mph. I tend to agree with HWKS1, that it's a safety function built into the ESC system.

 

[hwks1]

this is actually vey nice feature - and has nothing to do with any guard rail. The car senses lateral force and reduces speed...plain and simple.

Don't like it? Turn off the cruise or.... power through the curve!

 

[jnc2000]

Came across another gremlin. The SCC does not like something in or around the Pittsburgh Airport. I can duplicate this every time - and it's quite unnerving. When traveling inbound on I376 (with no other vehicles around mind you) the SCC will display a "caution / warning" on the DIS (within the instrument cluster). This sets the car into an immediate panic brake and will stop the car if you let it as the system senses a collision.

I'm going to record it with my HD Hero and show my dealer... this isn't right.

 

[pilotdane]

Does anyone know what radar system the Genesis has or what it's frequency is? I think all the automotive radar systems are in the W band at 76-77 ghz. When you get close the airport I wonder if the car is seeing some other radar or security device's output bleeding over into the Genesis' radar frequency. I think some airport/aircraft anti collision systems are somewhere in the W band.

It has really come to light lately that GPS receivers are very poor at looking at only their assigned frequencies and are quite susceptible to other uses of the radio spectrum on either side. It's quite possible that the car's radar is poorly/loosely filtered and looking at a "chunk" of the spectrum and not a narrow band.