Traction Control ??

[dtximages]

I made a right turn on newly damp roads yesterday and almost lost the rear end. The traction light blinked but I never "felt" the car correct itself. All of my other cars, you can easily feel when the TC kicks in.. Not in my 2019 Expy. Was it even working? Is this like the 4A that operates differently than other vehicles?

For explanation about what I mean about the 4A, I've posted about this before, it's different than other 4A's that I've owned. My Expy 4a is ALWAYS ON, not "auto on when slip occurs".

But anyway, this post is about the traction control. I felt there was a considerable amount of wheel spin and never felt the TC kick on. Am I missing something?

FYI, I'm very familiar with how other TC's work and feel and this was scary. Also, I'm well aware that TC doesn't mean you WON'T EVER slip.

 

[2020-MAX-Limited]

I am new to my 2020 Gen 4 Expy and only have the 4A version (not 4H or 4L that comes with towing). On my first drive in slippery/snowy conditions, I also experienced unnerving sliding a couple of times (rear end kicked out) when going around corners. I didn't notice if the TC light came on, but I did not feel the car take any corrective action. I will also admit I do not have the best tread on the tires; but since then, I pay more attention to the road conditions and also make a habit of using the Drive Mode dial to put the vehicle in Grass/Gravel/Snow mode that gives full-time 4A. If you simply press the 4A button, it only invokes AWD when the rear wheels slip/spin.

I learned in another thread that you can put up the Off-Road Power Distribution display that shows drive power going to all four wheels full-time when in Grass/Gravel/Snow mode. In Normal + 4A, the power is only going to the rear wheels unless rear wheel spin is detected.

All this doesn't explain why the car took no action to correct slip/sliding. The manual says we have Traction Control + Stability Control (unless you switch it off), but I guess the best thing to do is to experiment under safe conditions with putting the car into a slip/slide to see when/if it actually takes corrective action.

 

[dtximages]

With respect, I believe you're mistaken about the 4A in Normal mode. On the Expy, and to my surprise, 4wd is always engaged in 4a, its a matter of how much output is sent to the front. 4A in the Expy does NOT MEAN "2WD until needed" then kicks in the 4WD. You can see this on the offroad screen where going 50mph on dry roads it STILL sends power to the front. Not 100% power, but some here and there. It's very interesting and not intuitive IMO.

Anyway, I should NOT have to select my drive mode based on normal rain/slippery roads for the Traction Control to kick in and make corrections.

 

[2020-MAX-Limited]

With respect, I believe you're mistaken about the 4A in Normal mode. On the Expy, and to my surprise, 4wd is always engaged in 4a, its a matter of how much output is sent to the front. You can see this on the offroad screen where going 50mph on dry roads it STILL sends power to the front. Not 100% power, but some here and there. It's very interesting and not intuitive IMO.

I was basing my comments upon observing the off-road power distribution display. I was not going 50 mph, much slower, and was not seeing any power to the fronts in Normal and 4A at slow speeds. Maybe at 50 mph it always sends power to the front as you say, but I did not test it at those speeds.

 

[LokiWolf]

You are both right , kinda.

1) The power display is misleading. In 4A it will show the bottom of the front wheel power meter as being lit, even when power is not really being sent, as a visual you are in 4A.
2) On the 4A equipped with no 2 Speed Transfer, there is no 4H button, but some of the modes do actually engage basically 4H, with a more 50/50 torque split.

4A does basically mean RWD until slip is sensed then the TOD(Torque on Demand) Center diff sends power forward. The only difference is the front is ready for that torque vs 2H, so it happens in milliseconds. So at the most basic terms, "2WD until needed", with the caveat that the front driveline is spinning and ready for the power.

Now as far as TC not kicking in. Mine is over aggressive honestly, unless I double tap the Traction Control button to put it in Sport mode.

 

[gural]

LokiWolf
but when I go on 4A not on 2 i can hear that the car is much louder in the front
and i also see that there is a higher fuel consumption

tested on normal conditions on about 200 M distance

 

[LokiWolf]

LokiWolf
but when I go on 4A not on 2 i can hear that the car is much louder in the front
and i also see that there is a higher fuel consumption

tested on normal conditions on about 200 M distance

That is correct, because of the parasitic loss of the front drivetrain being engaged, but no power is sent forward unless there is slip. The front wheels are moving the front diff and drive shaft, not the motor.

Let's please have this discussion in 1 place about 4A/4H/4L/2H, please go to this thread:

4H / 4A / 2H

Noob expedition owner. Just want to make sure I am not doing anything wrong w.r.t 4WD / AWD First question: My 2022 expedition makes some weird sounds from the transmission when I am running on 4H at slow speeds. Is this normal ? I had just returned from a snow mountain trip to Tahoe (360...

www.expeditionforum.com

@dtximages Issue is more with Traction Control and not the ins and outs of the 4WD system. Let's get their thread back on track.

 

[sjwhiteley]

Is it likely you might have lost the rear end if TC was not active? Did it flash, but you missed it? I will often just catch the last flash or two if I look down quickly after slipping sideways.

I have found that the TC is a lot more ‘sluggish’ to respond compared to for example a BMW, with a very sophisticated traction and stability control system.

However, it definitely works. I have a grassy field to mess around in (by accident, of course!) and with traction control on, it will not do any kind of donuts. With TC off, well, it’d be all fun and games, until it isn’t…

 

[Soliyou]

Before buying my expy, I rented a 2017 2wd for a family trip. I floored it on the highway going in straight line (to pass) in the rain. Lost the rear end but was able to correct. No intervention from the TC ever. When I bought mine, I made sure to get it with 4A. In any rain or snow I put it in 4A.

 

[gural]

got everything clear

 

[Deadman]

Gosh I wish mine was less invasive. In any snow, the damn traction control cuts ALL the power and then the retarded trans thinks it should shift up 2 gears. Then the TC gives me back the throttle and now its 2-3 gears too high and takes a few seconds to shift back down into a reasonable gear, and THEN we can finally start moving forward again. Its ridiculous. I wish it wasn't there, and its too much BS to fiddle with to shut it all off every time I restart the car.....

 

[2020-MAX-Limited]

Gosh I wish mine was less invasive. In any snow, the damn traction control cuts ALL the power and then the retarded trans thinks it should shift up 2 gears.

Are you in a 4x4 mode? I've never experienced a wheel slip or TC activation when in 4x4.

 

[Deadman]

Are you in a 4x4 mode? I've never experienced a wheel slip or TC activation when in 4x4.

Sometimes yes, sometimes no. Its annoying when there is just a little batch of ice by an intersection and I'm in 2wd and it slips and kills all power. I keep 4A off when I don't expect to need it as it wears the front end out by spinning everything for no reason.

 

[dtximages]

OP here and update: We just had ice/snow in Texas and I was able to play around with the TC and 4A.

1. I think the TC is different in this car as it doesn't jump/jerk, it simply lowers power drastically but it's smooth feeling and causes me to believe it's not working.
2. 4A worked very good in the ice/snow
3. Michelin CrossClimate tires are awesome in this weather!

 

[Calidad]

So today’s vehicles get stability control systems tied to what drivers often call traction control. Each vehicle gets a level of tolerance for traction loss based on the design of the vehicle ie the vehicle stability envelope.

If your prior vehicle was older and / or had reduced stability you would definitely notice the “traction control” systems being more aggressive regarding chopping power to prevent an uncontrolled skid.

I have noticed that the Expedition nanny is far less aggressive than my Toyota Sequoia. Thats going to have many reasons including the inherent stability designed into the Expedition
.
Also super aggressive nannies that cut power at the slightest loss of traction can cause serious performance issues and definitely trigger angry owners
.

My Sequoia occasionally would totally cut power to zero on right hand turns in the right conditions ie up hill street it would bring you to a dead stop mid turn. Well known gripe with the Sequoia owners

 

[Calidad]

OP here and update: We just had ice/snow in Texas and I was able to play around with the TC and 4A.

1. I think the TC is different in this car as it doesn't jump/jerk, it simply lowers power drastically but it's smooth feeling and causes me to believe it's not working.
2. 4A worked very good in the ice/snow
3. Michelin CrossClimate tires are awesome in this weather!

Tire’s definitely make s huge difference. The oem tires were terrible at 15,000 miles I couldn’t take the constant sliding anymore even wet pavement they were traction challenged. BFG trail Terrain new 3peak a/t tire for SUVs. Massive difference not even comparable 2whl with these tires can get thru snow that 4whl struggled with.