Engine Stall during Hill Assist

The entire hill was not ice. Just near the top. The very second I started going backwards due to the stall, I went to the brakes. Nothing.

I had gone up and down that hill 3 times that day. So brakes were working just fine going down on the packed snow when the rig was running. Later in the day a spot at the top re-froze and the incident happened.

This was a little while ago and I just cannot stop thinking about it.

Thanks for all who responded. Seems like it is working the way it should. I suppose I just don't like it for this particular reason. I know how to drive and do not need the car to try to do it for me.

In a rig without this feature, I would have come to a stop with the wheels spinning. Apply brake, slowly back down the hill or park it where I was.

I should add, where I stalled out was not at all that steep. It was cresting to the top. I did not slide down the hill. I rolled down.

Thanks again!

 

As if I was driving? I mean yes, they technically work, but I would not call them power brakes. After a few pumps the pedal stopped depressing just like when in Park.

 

They would work like normal. It's an electric pump, not engine vacuum boosted. You can pump the brakes with the ignition on and the engine off. The pump will activate when the pressure drops below the set threshold to bring it back up.

 

Did not know that. Good to know!

 

To the OP: What year 4runner do you have? Maybe the earlier models have a regular brake booster? I know that 2wd 4runners have a regular vacuum brake booster.

 

Did you try the E-brake at all?

 

Hahahaha

Sorry for the chuckle. It’s because Im happy that mine will hold it still on a slight incline. But I guess it’s always worth trying the parking/e-brake, even it’s just a token gesture.

 

Sounds to me like maybe you were on the gas with the tires slipping on the ice and started sliding backwards, then at some point you were off the throttle and brake, so the tires started ROLLING backwards due to the momentum for long enough to stall the engine and then you got on the brakes after the engine stalled, and maybe there was more ice again that you slid on. The brakes should’ve still been functioning so not sure about that. Sounds kinda like maybe the situation caught you by surprise and you aren’t remembering the exact sequence of events clearly.

I’m also curious about your initial post saying you slid all the way down the hill, and then you changed that to the ice was only at the top of the hill. With that and saying the brakes completely not functioning, I feel like things aren’t adding up to the full, actual story. Brakes are power assist, so even if you did somehow lose power assist, you can still press hard on the brakes and stop the vehicle, especially at the low speed you mention, since you were only on ice at the very top. With traction, you’ve got plenty of strength in your leg to stop, and I imagine rolling backwards down a hill, you’d be jumping on the brake pedal pretty hard trying to stop.

 

Yeah, mine doesn't work worth a shit; however, I've driven my sisters 2022 and hers works as it should.

All I'm saying is if I was sliding backwards down a hill with no breaks, I'd sure as shit be mashing that e-brake into the floorboard......whether it works or not.

 

After a 12 year career as a tech I went into automotive engineering. The development cars were outfitted with extensive data logging equipment and cameras. Over a 6+ year span I can count on 1 hand the number of instances that a driver’s first hand account of what happened was accurate.

 

Odd it would have stalled in 4lo. I can have my 21 on a steep incline and in Drive in 4lo and the engine holds it there just idling, doesn't roll back at all.
Add ice to the equation and it would just spin.
Been my experience you want 4h for ice. 4lo has to much torque. Need to lug the engine. Used to drive quite a bit on the frozen lakes. Stick shift is better yet, you can up shift till the tappets start
clattering.

 

2015 SR5 4WD

 

Well there was snow on the hill, icy only near the top where other rigs had packed the snow down and it melt and refroze.

And yes I was on the brakes really hard. I guess I was just still sliding with locked up brakes at that point.

I went from spinning tires on the ice to applying the brakes as quickly as one can do.

I had no clue I had stalled out until I came to a stop and tried to turn around and go another way.

Thanks again for all the help, ideas and suggestions!

 

I never knew this stalling thing with automatics. Good post.

 

And manuals if you dont push down the clutch.