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Discussion Starter · #1 ·
Hello guys,
I'd like to discuss an issue or "known issue", or even "feature" :) when Cherokee stuck on a slope or in small hollow. However a driver press "pedal to the metal" but Cherokee just stops going and wheels stop spinning. There are tons of video in youtube with this behavior from different astonished people. For example
The man from the video switched on "4wd low" and tried to overcome snow slope but Cherokee just stopped.
I think root cause of this behavior is "torque model" and when requested torque is more then actual it stops. However maybe i'm wrong.

Tyler: as far as i remember you've increased allowed torque per gear in your vehicle in ECU or TCM. So have you had faced with this "issue" before the changes with torque and does it appear now?

Everyone: If you have faced with the above- how have you tried to overcome it?
Or it's only my issue and guys from youtube? :)
 

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It's probably just from being in snow mode and having all the tires slip. Most AWDs do the same thing. The AWD system will clamp down on the spinning wheel, but if all wheels are spinning, there is no way to go. Being in snow mode, the traction control will be most aggressive and allows less wheel spin, therefore causing this issue sooner. If they had put it in sand/mud, it would have relaxed the traction control and let the wheels slip more, therefore not cutting the power, at least as much or as fast. He would have been better just leaving it in auto, however, I'm not sure that was much different than what most people who own a jeep would do. If you watch some of the TFL videos on youtube, they test a lot of different AWDs offroad, and the cutting the power to all wheels is fairly common.
 
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Discussion Starter · #4 ·
It's probably just from being in snow mode and having all the tires slip. Most AWDs do the same thing. The AWD system will clamp down on the spinning wheel, but if all wheels are spinning, there is no way to go. Being in snow mode, the traction control will be most aggressive and allows less wheel spin, therefore causing this issue sooner. If they had put it in sand/mud, it would have relaxed the traction control and let the wheels slip more, therefore not cutting the power, at least as much or as fast. He would have been better just leaving it in auto, however, I'm not sure that was much different than what most people who own a jeep would do. If you watch some of the TFL videos on youtube, they test a lot of different AWDs offroad, and the cutting the power to all wheels is fairly common.
I've even managed to reproduce this issue with "4wd low" and "Rock mode" on. Therefore snow mode isn't root cause of it, i think.
 

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I've even managed to reproduce this issue with "4wd low" and "Rock mode" on. Therefore snow mode isn't root cause of it, i think.
Rock mode also has a very aggressive traction control. If your on rocks, the goal is to transfer the power to the wheel that has grip. Spinning the wheel more will not give you more grip, so it clamps down on that wheel. If you get in the same situation and it kills all the power, switch to sand/mud. Generally, that's when you would have the highest chance of breaking something though.
 
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Also in Rock mode, your limited to 1st gear, so you won't get much wheel speed out of it anyways.
 

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Yep ^^. Just disable traction control, and go.
Now this is a good option, and I'm actually surprised he didn't do it. I have seen him do it with other vehicles in the past, and almost certainly would have kept from killing the power. Plus this is also something I could see the average driving doing. Maybe not holding it down for 10 seconds, but at least hitting the button, which should help.
 

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Discussion Starter · #9 ·
Now this is a good option, and I'm actually surprised he didn't do it. I have seen him do it with other vehicles in the past, and almost certainly would have kept from killing the power. Plus this is also something I could see the average driving doing. Maybe not holding it down for 10 seconds, but at least hitting the button, which should help.
But if "4wd low" is switched on it automatically switches off TCS system at least it displays this on the dashboard.
 

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This is what happens when you're in 4low and in any of the modes while the transmission isn't locked into a gear. If he had manually shifted into 1st or 2nd gear, it avoids the transmission revving up and attempting to switch gears while finding major wheel slippage thus stopping all movement. This is the only time that has happened to me, manually shifting has fixed the issue while providing more control in situtations that I needed.
 
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Now this is a good option, and I'm actually surprised he didn't do it. I have seen him do it with other vehicles in the past, and almost certainly would have kept from killing the power. Plus this is also something I could see the average driving doing. Maybe not holding it down for 10 seconds, but at least hitting the button, which should help.
I've had similar happen in winter, stopping on a snow plow berm and having zero power for a few seconds. Holding the ESC button (5 seconds ?) gets you ESC full Off, hitting it is partial Off. Partial Off should be Ok, but I'd go full Off.

Interesting about 4 Low : of course ESC is Off, but what @Housekat23 reports confirms it can happen. I don't have AD2 so I can't try ;)
 

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ESC is not off in 4low, just like it is not off in sport mode, but you get the same light. It's basically letting you know the ESC is not at the same level as if you were on the road. If it truly turned it off, there would be no need for the dial, and some situations the ESC is helpful. The different modes uses the ESC to help in situation you are encountering. For example, you don't want the ESC to slow down your momentum when in sand or mud, so it lets you spin more than without. On rocks you need the control and spin the tires could slip you off your line. In snow, a little sideways could turn into a lot sideways, so it's going to try and prevent that early. The electronic brake differential can never be fully turned off, so you will always have that. Also, if you go over like 40 mph, it will reengage ESC.
 

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But if "4wd low" is switched on it automatically switches off TCS system at least it displays this on the dashboard.
To a varying degree based on mode.
Sand/mud mode is full off traction control, it will not engage in this mode and you can spin the wheels to your heart's content.
reference:
 

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ESC is not off in 4low, just like it is not off in sport mode, but you get the same light. It's basically letting you know the ESC is not at the same level as if you were on the road. If it truly turned it off, there would be no need for the dial, and some situations the ESC is helpful. The different modes uses the ESC to help in situation you are encountering. For example, you don't want the ESC to slow down your momentum when in sand or mud, so it lets you spin more than without. On rocks you need the control and spin the tires could slip you off your line. In snow, a little sideways could turn into a lot sideways, so it's going to try and prevent that early. The electronic brake differential can never be fully turned off, so you will always have that. Also, if you go over like 40 mph, it will reengage ESC.
ESC is off in 4-low. The only thing active is the Brake Lock Differential feature of the ABS system, and that's only active on the front wheels if the rear axle is locked, if the rear axle is not locked then the brake lock differential is active front and rear.

All of this can be avoided by simply using ESP full off which is available in any mode in 4-high. ESP full off is every part of traction control disabled (engine power limiting, brakes stopping the wheels from spinnin [different from the bld]) the only thing active is brake lock differential. All selec terrain does is change the brake lock differential programming and control transmission shift schedule

That video simply had the operator not knowing how to use the features and traction control system on this vehicle he was driving.
 

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All of this can be avoided by simply using ESP full off which is available in any mode in 4-high. ESP full off is every part of traction control disabled (engine power limiting, brakes stopping the wheels from spinnin [different from the bld]) the only thing active is brake lock differential.
I assume that would be appropriate for dry conditions too?

I recall an episode the very first time I took my TH on a trail. There were several fairly steep but short inclines on otherwise mostly flat or slowly inclining terrain (dry gravel and dirt two-track) so switching into 4-low didn't really seem worth it. Definitely I'd never have even considered 4-low in my old WJ. But on one particularly steep incline the computers just refused to supply torque to the wheels despite gradually pressing pedal until it was all to the floor. It just barely made it up without having to stop and shift into 4-low.

I assume it's there to protect the drive system from tearing itself apart but it's nonetheless pretty annoying if you aren't aware it's going to do that. The WJ would do almost anything i normal 4-hi, low only needed in pretty extreme circumstances. My experience is the KL has to be driven quite differently with more planning since you can't just rely on the loud pedal to get you out of trouble in vanilla auto mode.

I'd say snow mode (or TC off) seems like a good start for those kind of conditions too, at least it's worked for me since.
 

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ESP full off on dry pavement it totally fine, no issues using that mode. ESP full off and auto mode is good for almost everything, if you can't move in that mode then it's time for 4-low
 

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That video simply had the operator not knowing how to use the features and traction control system on this vehicle he was driving.
I'd have to agree with that. I've never had the power cut off on me during in 4 low driving and in much, much worse snow/mud conditions than those guys did.

Add: Maybe if someone over-heated the tranny it could cut power? I've never had this happen btw, just a guess ...
 

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I'd have to agree with that. I've never had the power cut off on me during in 4 low driving and in much, much worse snow/mud conditions than those guys did.

Add: Maybe if someone over-heated the tranny it could cut power? I've never had this happen btw, just a guess ...
The clutches in the RDM will overheat before the transmission, frequently happens if you are wheeling hard in 4-high. 4-low solves the problem as the clutch packs in the RDM are locked so minimal slipping
 
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