What's up with the Traction Control?

[mdbuilder]

Any knowledge of how the TC is supposed to work?

Pulling out of a T intersection today on very wet roads I made the 90 degree turn while accelerating -umm, rather smartly . A wheel spun and the rear slid a bit in the beginnings of a spin, at which point I reduced throttle / recovered traction and continued on my way.

No TC warning lights seen, seems odd and different than other vehicles I've driven. My old Miata for instance would not allow the wheel spin at all. Unless I turned TC off of course...

 

[siai47]

The I-MiEV has a traction control system and a stability control system. Both are active at each ignition? (ready) cycle. The TCS is active at all speeds, stability control above 9.3 miles per hour. The TCS should have done something when you encountered wheel slip. That something is as follows: 1. It should have applied the brake on the spinning wheel (via the ABS pump). 2. It should have reduced power to the motor. 3. You should have seen the TCS light (lower left on the IP) flash during the time it was actively controlling the slip. It's possible that the wet conditions might have had the rear brakes a little wet. We all know drum brakes don't work well until they dry out from use. All of us old people remember that you needed to drag the brakes a little bit every couple of minutes to keep the linings dry in the event of a panic stop situation. With non-power assist drum brakes on my '59 Chevy, every stop was a panic stop! Even though you got some wheel spin, you should have heard the ABS motor, which is located on the left front frame rail, run for a moment. I don't think I would be looking at the TCS light during a turn so that might not be noticed. Suggest you try a turn (under controlled conditions like a wet parking lot) and see if you can duplicate the problem and look for the indicators that the system is working or trying to work.

BTW---turn the TCS "off" and see how many donuts you can do :lol: !

 

[mdbuilder]

While I was out since the first post I repeated the experiment a couple more times without the traffic <g>. The system works, it is just much slower to react on the initial traction loss. The car will yaw about 5 degrees or a little more before it kicks in and stops the skid. Just different. On this first incident I reacted is just before or just *** the system was reacting.

I guess the 9.3 mph thing is good for driving in snow. My Nissan NV200 front wheel drive van is unusable from a standing start in deep snow with some ice underneath, the TC allows no wheel spin at all. The only way to get moving is to turn it off...

 

[PV1]

I had some fun during my first i-MiEV winter. The road was slush/borderline ice. I had to a make a left turn at a large intersection (physically large, no other cars at the time). In mid-turn, I floored the throttle. The car kicked out on the slush, but when the ASC kicked in, the car stopped its skid completely and continued motoring forward. I was very impressed that it halted a skid almost immediately in the middle of a turn.

So, the ASC will allow the back end to kick out a little, but too much and it'll put a quick stop to it. Turn it off, you're going around in circles :lol: .

 

[mdbuilder]

Yep, that's kinda why I made the post - exactly how does this system work in real life because it seems much less aggressive in terms of not allowing any instability compared to other cars I've driven with ASC. That's fine, just wondering. Now I've got a feel for it, you basically should be driving the car within limits and it is there just in case to save you vs. my old Miata for instance where you could use the ASC to exit a corner under full acceleration right at the limit of adhesion.

 

[JoeS]

Another interesting peculiarity of our i-MiEVs is the interaction of Regen and ASC, especially noticeable on sweeping downhill curves when hitting a rough patch on the road surface at high speed - the regen disconnect and chattering of the wheels is 'interesting'. Even though I turn off ASC when tailgating Porches or Beemers on twisty windy roads, I'm very happy to have ASC for everyday driving, especially for family members.