Traction Control ??

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.

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.

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.

dtximages said:

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.

Click to expand...

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.

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.

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

gural said:

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

Click to expand...

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:

@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.

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…

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.

got everything clear