Car moving forward when at complete stop on ice and brake applied

[7Andrei7]

I had the same problem 2 years ago, during a snow storm. Was driving on very icy roads and I simply could not stop the rear wheels moving unless I would put it into N (mine is rwd).
When coming to a hold, if I left it in D the rear wheels would try to push the car and the rear of the car would slide gently to one side (it was super slippery). This was happening with brakes fully applied.
Few months after that I found out my torque converter was faulty and it was replaced on warranty. I don't know if the two issues were connected. It never happened before or after that day.

 

[GT Elite]

I Here’s a thought about what the OP experienced.
I wonder if this is a “bug” in the ABS software. The reason I say this is that the ABS was active when the vehicle came to a complete stop, so the ABS may assume that it is no longer needed and returns the car to a normal driving condition; that it was in before the ABS was activated, which is to say to apply the throttle at the level it was at before brakes were first applied, even though the brakes are still applied…..somewhat. Given the extremely low traction condition there would be insufficent traction at the front to hold the vehicle In place.

in response to the comments about the brakes can stop a car at any speed with the throttle applied, that is true. However, there is NO LONGER a direct connection from the brake master cylinder to the brake calipers, as all brake pressure must now pass through the ABS system and if it is wrongly interfering it may limit the brake pressure to the back wheelor or both front and back regardless of how hard the brake pedal is pushed.

if this is the case, the best thing to do is to activate the parking brake to “essentially” have the ABS relinquish its control. I wonder if pumping the brake pedal may also do the trick.

 

[rpoffen]

I Here’s a thought about what the OP experienced.
I wonder if this is a “bug” in the ABS software. The reason I say this is that the ABS was active when the vehicle came to a complete stop, so the ABS may assume that it is no longer needed and returns the car to a normal driving condition; that it was in before the ABS was activated, which is to say to apply the throttle at the level it was at before brakes were first applied, even though the brakes are still applied…..somewhat. Given the extremely low traction condition there would be insufficent traction at the front to hold the vehicle In place.

in response to the comments about the brakes can stop a car at any speed with the throttle applied, that is true. However, there is NO LONGER a direct connection from the brake master cylinder to the brake calipers, as all brake pressure must now pass through the ABS system and if it is wrongly interfering it may limit the brake pressure to the back wheelor or both front and back regardless of how hard the brake pedal is pushed.

if this is the case, the best thing to do is to activate the parking brake to “essentially” have the ABS relinquish its control. I wonder if pumping the brake pedal may also do the trick.

ABS, there’s a thought, I mentioned it in a previous post on this thread (#30).

 

[JSolo]

Wouldn't have these stupid problems if the car was MT. In fact trans would be much simpler.

 

[Snicklefritz]

Wouldn't have these stupid problems if the car was MT. In fact trans would be much simpler.

a manual trans stinger would have sold 1.5 thousand cars total. but if kia had offered a manual option I would have taken it. Ima special.

 

[JSolo]

To the OP, check out the videos in this post. Wild!

Car rolls when parked on a snowy incline - MyG37

Engine, Drivetrain & Forced-Induction - Car rolls when parked on a snowy incline - Ok so after lurking here for over a year, I finally bought myself a 2011 G37x a week ago today. It's got about 150,000 km on it and a clean carfax. I live up in Nothern Ontario, so I had to travel about 4 hours...

www.myg37.com

 

[Thomby]

To the OP, check out the videos in this post. Wild!

Car rolls when parked on a snowy incline - MyG37

Engine, Drivetrain & Forced-Induction - Car rolls when parked on a snowy incline - Ok so after lurking here for over a year, I finally bought myself a 2011 G37x a week ago today. It's got about 150,000 km on it and a clean carfax. I live up in Nothern Ontario, so I had to travel about 4 hours...

www.myg37.com

That doesn't look like the same scenario -- OP in this thread said he's in gear with brakes applied, and car is idling forward. In the Infiniti thread, he's rolling while in Park (second video shows fronts rolling, not sliding), and the girl in the video says she applied the brakes to stop rolling.

A few in the Infiniti thread suggest he has a broken Park pawl, but the left rear spinning backwards would indicate the transmission output is locked.

If the front tires are in neutral (Park doesn't lock them) and the car is on a slick hill, once one of the rears loses traction, the one with traction will be spun by the car's motion, and the one without will spin backwards via the differential.

 

[JSolo]

^^I don't think it is the same scenario, but it's odd to see a back wheel rolling in the opposite direction as the front (at least on the driver side). Pass side appears to be rolling properly.

I posed the question to a friend who's an ase master tech. He thinks either something wrong with the brakes or brake control system to cause the behavior the OP is describing.

 

[Thomby]

^^I don't think it is the same scenario, but it's odd to see a back wheel rolling in the opposite direction as the front (at least on the driver side). Pass side appears to be rolling properly.

That's just how a differential works. If the input/driveshaft is turning, at least one of the wheels will turn. If the input is locked (via the parking pawl), turning one wheel forward means the other has to spin backward.

In the link below, imagine stopping the ring & pinion (blue & green). The cage that holds the orange spider gears can't rotate any more, so the spider gears will reverse the direction between the half shafts (red & teal):

http://thecartech.com/subjects/auto_eng/Auto_Eng18_files/image006.gif

 

[G-485078]

This happened to me today. First snow/ice of the year and I was stopped completely on snow while pulling out from my son's school. Suddenly the car began inching forward into the road. I further smashed the brake as hard as I could and it did nothing (if anything it started moving faster). I tried steering to the side to prevent going into traffic and then it just stopped and was fine.

I read through this thread and really can't figure out if anyone has an answer for this other than to put the car into neutral. I can do that, it was just a bit jarring thinking I was going to get t-boned.

 

[stinger123]

This happened to me today. First snow/ice of the year and I was stopped completely on snow while pulling out from my son's school. Suddenly the car began inching forward into the road. I further smashed the brake as hard as I could and it did nothing (if anything it started moving faster). I tried steering to the side to prevent going into traffic and then it just stopped and was fine.

I read through this thread and really can't figure out if anyone has an answer for this other than to put the car into neutral. I can do that, it was just a bit jarring thinking I was going to get t-boned.

I am the OP and this still happens to me intermittently under specific conditions on ice after coming to a complete stop. It hasn't yet happened this winter, but I haven't been driving much. The dealer "couldn't replicate it" and didn't seem to care when I took the car in in early 2023. I found that it seems less likely to happen if I warm the car up for a solid 5-10 mins before driving and I also use auto hold now with any icy conditons. If it happens with auto hold, typically my car just starts revving and trying to pull forward but at least stays in one place.

It must be some type of ABS or electronic issue. My brakes are fine otherwise. It's like the car thinks it is still sliding and not fully stopped and starts trying to correct things or something.

 

[D.J.]

I was stopped completely on snow while pulling out from my son's school. Suddenly the car began inching forward into the road. I further smashed the brake as hard as I could and it did nothing (if anything it started moving faster). I tried steering to the side to prevent going into traffic and then it just stopped and was fine.

This sounds like you are describing sliding (all 4 wheels locked)...., and then eventually gaining traction.
Too bad you didn't have a dashcam to show the conditions/scenario.

weird.