Hesitation/Rolling Stop Problem

[fantasia]

Hi
I am a newcomer to this site, referred to by a friend recognizing a problem that we were experiencing with a 2015 Genesis.
We took possession of the 3.8 on January 19 of this year and within the first couple of days started to experience a hesitation with acceleration. It is like a dead spot where the pedal is depressed and nothing happens. This hesitation was random, would sometimes occur coming out of a turn and has also occurred when doing a lane change. We have also experienced this hesitation when coasting up to a red light and before coming to a complete stop, stepping on the pedal and having nothing happen. A second or two later, it seems like something catches up, and there is this surge of power.
Interestingly, this is our second Genesis. We leased a 2009 with all the luxury packages and were extremely happy with it. As a matter of fact, we were so happy with it, we ended up purchasing at lease end and drove it for three years until trading it in on the 2015. The 2009 was trouble free and we never experienced any hesitation problem, although research on this website seemed to indicate that this was a problem on many 2009 to 2014 Genesis models.
Naturally the 2015 has had several visits to the dealerships, some for overnight stays. It has had "black boxes" installed to monitor our driving habits. We have discussed my two feet driving style as a potential problem, however have not been able to understand my wife's one foot style while also having the problem. Dual mats have also been considered.
They have not been able to say what the problem is, although it has occurred on one occasion with the service manager in the car.
I am at wits end with this situation primarily because of the safety factor. It is something to consider when making a left hand turn or a fast lane change not knowing if there will be a hesitation in front of oncoming traffic.
A little wordy this is, however I wished to state my case and see if in fact as we are being led to believe, that we are the only Genesis owners in the universe having this problem. Any feedback would be greatly appreciated.
Thank you,
Bill

 

[homeofstone]

Have they changed out the accelerator pedal sensor. It is a drive by wire accelerator pedal and it may be an intermittent problem with it.

 

[Analog]

Need more data to help!

- How hard are you stepping on the pedal? A tiny bit, a medium amount, two inches, floored, etc.

- What happens normally when you step on the pedal? Instant response or a short hesitation, and this hesitation is super long in comparison? Yes I understand two seconds feels like an eternity when you are expecting power and it's completely absent. Don't be afraid to report accurate figures like you have been.

- Is there really a dead spot in it's travel, like it's random but when it does happen it's always between .5" and 1.5" of pedal travel?

- Is cruise control on? I notice pretty dramatically different throttle response when cc is on versus off. (or rather, active vs inactive, both are technically with the cc system on)

- Are you always in normal mode, or sometimes in sport or eco or snow? Maybe try sport mode for a week and see if the problem is still there. That rules out hardware vs software failures.

- When the black boxes were installed, did you log date & time stamps of when you or your wife experienced the problem so their engineers could correlate data to the problems?

If I were you I'd use my dashcam footage to provide additional evidence, both to you and to your service team. Let me know if you want a link to an inexpensive dash cam that is highly rated on dashcamtalk.com, along with a good memory card to use with it. I'm not going to link it now because I don't want to seem like I'm pushing any particular product. Personally I verbally note that it just happened (perhaps with lots of colorful words?) + the time, then would press the lock button so the recording could easily be identified amongst all the other recordings.

I doubt the floor mats could be causing problems, though it's not advisable since the toyota unintended acceleration problems to run with two floor mats (plus, aren't you limiting what flooring it really does??)

The two foot driving style could be to blame, but none of us will be able to help there. We would have to look at the black box data combined with your reports of when it happened to see if the two are correlated.

I bet that what feels random actually has a sensible explanation, that is only clear once quite a few of these incidents are viewed in succession. I know that's a pain to get but you've already done most of the work!

Fwiw I do not feel like my 2015 hesitates at all. My 2012 had a nasty hesitation problem but that was only at very low speeds, always <5mph. As I identified the problem I learned what habits caused it to hesitate and worked around it. Your problem sounds like a safety issue and not relegated to certain speeds or conditions, so I wish you the best of luck!

 

[Pahaska]

Good answer above. My 2009 had the hesitation problem. As noted above, I learned to compensate for it early on. My 2015 is letter perfect in this regard. When I need power, it is there instantly.

 

[PMCErnie]

Drive another '15 at the dealer and compare.

 

[fantasia]

WOW! Thank you for the responses. Will definitely ask about the accelerator pedal sensor. Now regarding more data:I kind of look for a smooth start and when making a turn, I think I have my foot lightly on the pedal and as I come out of the turn I start to depress further and sometimes I get a smooth acceleration and on some, nothing for a moment or two, then the surge of power. The same scenario plays out sometimes with a lane change or with that rolling stop coming to a red light or coming up to slowed traffic, then stepping onto the pedal to accelerate. I do not know the exact distance as I go from slightly on the pedal, then through what would be the slow acceleration range to way down and the power surge pushing you back into the seat. On occasion this has almost evolved into an over steer situation. No cruise control on. Used in normal and eco so far with no noticeable change. They installed a unit in the cigarette lighter and another in the fuse box opening. We were told to press a button on the one in the cigarette lighter port when we had an incident, which we did. At their suggestion I removed the extra mats. Although an advocate for the two foot driving method, I was extremely careful not to rest my left foot on the brake which they suggested might be the problem. I guess what surprises me is that, driving the 2009 for 6 years and not having any such problem in a car that supposedly did have this problem, and within days of getting the 2015, I started having the problem. Frustrating! Thanks again.
Bill

 

[joeyz400]

Try holding.the trac-control button for 10 seconds. This will disable the track and stability control. See if you still get that hesitation.

 

[Analog]

The difference between a 2009 and 2015 is probably the logic in the car's brain. That being said, with the data you said they collected including timestamps of when it happened, I'd say it's a pretty fair bet it's not your two footed driving style. That's what they would have zeroed in on. In fact they probably got tunnel vision, and when they didn't find any brake applied during the incidents they fell flat on their face. If they had found brake applied they would be blaming you instead of the car without a second's hesitation, and rightly so.

So I'm going to echo what others have said: it's probably an issue with the throttle position sensor, or the car's controllers which are responsible for interpreting that input. Action depends on what they're willing to do. It's probably easiest if you asked for a similar (preferably identical) model for whatever the maximum interval between problems has been. If they refuse that, which they are somewhat likely to, then ask for them to replace parts related to pedal position sensing and/or interpretation.

If they refuse that based on their inability to reproduce in a short amount of time, offer to take a loaner while their service manager (or lead technician) drives your car. You might want to go on an initial outing to make sure they're driving the car the same way you do, to maximize their chances of reproduction.

If you're not comfortable with that, the only remaining option is to buy a couple ~$50 dashcams (plus memory cards) and have one focused on the road and the other focused on your feet. The combined output should be able to prove that it is happening - and that it's not your two footed driving style - without losing your car for a while.

Hope this helps!

 

[fantasia]

Hi all, and thanks again for the information.
I did suggest the accelerator pedal sensor replacement however that was not taken as a solution. They were receptive to me driving a loaner and provided a new Genesis which we drove for two days without any type of incident. It was completely trouble free and a pleasure to drive. Unfortunately since returning to our car, we have continued to have the same problem. We have had several meetings trying to come up with a solution and hopefully this will work itsself out. Thanks again, and will let you know how we make out.

 

[joeyz400]

That is unacceptable ....... I would ask for the dealer have a tech drive your car with you in it then do the same with the new loaner. See if the tech feels the difference and then he might be able to diagnose the problem better.

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[ckon]

Does this happen all the time or only when the car is not yet up to full operating temperature? I've had it happen when the car is not yet full temp and I assume it's either an emission command or a "protection" of the hardware because of not being full temp, but I may be off base.

 

[amartz]

Do a little searching for the threads about modifying/removing the air flapper in the air filter box. This has been the biggest source of hesitation for off the line / rolling stops.

 

[Analog]

Assuming the OP drove the loaner under identical conditions there's no more doubt: something is definitely wrong with their exact (owned) vehicle. Not the 2015 genny line in general. The only question is the exact failing part.

As long as fantasia has the ability to reproduce or otherwise demonstrate (via dashcam or their logging facilities) that their vehicle is exhibiting the problem, he/she should be able to convince the dealer to replace parts until the problem is fixed.

 

[fantasia]

One of the problems has been, that I have only been able to reproduce the problem once with the service manager in the car. He definitely agreed that there was a hesitation or what seemed to be a dead spot in the pedal that one time. At this past meeting, a representative from Hyundai rode with me and later took over the driving, both of which went flawlessly. Unfortunately, after leaving the dealership and at the stoplight, when the light changed, the pedal was dead for a second or two before surging ahead. There does not seem to be any discernable pattern regarding usage, heat, cold, rain or dry, city or highway. Extremely frustrating problem.

 

[Analog]

What you need is evidence. Tons and tons of evidence. Buy a dashcam and attach it to the glass of your sunroof, aimed mostly at you but catching some of the road conditions too (they have crazy wide angles so should be able to get both, though I guess I'm not sure about the lighting involved.) Even if you just point it out the front of the car attached the windshield you'd still get very visible evidence of the car surging forward after not moving at all, in a situation where you'd normally be moving.

I feel for you, as it is crap that you'll have to do this after buying a new car especially when the old one was problem-free. I went through a similar ordeal where it was left to me to figure out what the problem was. The service dept is pretty worthless unless a problem can be reproduced every single time x or y happens.

You've made good progress by determining the problem is with your car rather than a problem with you (which obviously would have been a problem with the loaner too.) Keep on it! The dashcam I have is about $55 and the memory card around $5-15, it records in 1080p with decent enough quality. Personally I think of mine as cheap insurance, preventing a lot of he-said-she-said situations in the case of an accident.

Hope this helps!

 

[mfrish]

Actually, I think I'm experiencing exactly what you're talking about. I've had my 3.8 for about a month now, and this has happened to me 3 or 4 times. Typically it happens right after I make a right-hand turn from my neighborhood into a main street. I press the gas about 75%, and the car seems to take a few seconds where nothing happens, until I finally hear and feel the engine revving. I'm typically in Sport mode at the time.

Other than these 3 or 4 instances, I don't experience any hesitation. Your first post says something about yours hesitating after making a turn. I wonder if it could be traction control or something...

 

[Analog]

I wonder, fantasia is yours RWD or AWD? mfrish's appears to be RWD based on his/her sig where presumably AWD would be listed alongside Signature (maybe.)

I can tell you in my AWD model I can mat the gas and take a pretty severe corner right off the bat and receive full power right away. My 2012 only hesitated if I were to start moving forward, then brake but not FULLY stop (such as pulling up to a stop sign, then pulling forward to get a better view,) then give it lots of gas. It was dangerously bad, but I learned to work around it.

I have also experienced power being cut in both models due to traction control (and stability control in the 2012.) It does not sound like what is being experienced here - I could be wrong though. I say that because tc or sc usually apply the power and then cut at a certain point, rather than delay the response.

Great to have another person experiencing similar symptoms, at least in terms of troubleshooting. Stinks that it is happening to both of you though, of course.

 

[amartz]

My 2012 had the same hesitation. It doesn't any more. There *is* a fix. Just search for the discussions about the air box flapper door.

 

[Midwestuser1]

I have not had this happen on my 2015 AWD Ultimate and I'm at 12,000 miles now. I did experience this on my last car 08 A6 quattro 3.2 though. Genny seems to have better transmission logic than my Audi had.

 

[amartz]

The hesitation has nothing to do with transmission logic.