ABS/Traction control seems to calm down when NOT in Eco mode...

While mine is significantly more susceptible to this than is my AWD Subaru, it is no worse than its FWD predecessor. Uphill takeoffs on metal covers or polished tar were/are worst, especially during the first rain after months of dry weather.

Anyone accustomed to winter driving should be able to reflexively respond to this.

The 'pause' here is nowhere near a full second. Bob Wilson measured it as closer to 0.3 second. And I believe that 'bad' version is not solely from ABS, but from regenerative braking cutting out and needing to switch to friction-only braking. Regenen-only braking is used just for light to moderate braking, it cannot produce stronger levels in this era Prius.

ABS should cut friction braking only to the affected wheel, not the other 3 wheels, so any pause or cutout should be far less discernible and alarming than the Regen cutout.

I commonly steer around most potholes. When that is not practical, pressing the brake harder before impact may engage friction pads so that ABS can keep the other wheels engaged. Though hitting potholes with brakes firmly engaged may be undesirable for other reasons.

This is an absolutely essential skill for serious winter driving, so was baked into my driving style and reflexes from the start.

Or brake harder before the pothole, then relax while going over.

I haven't noticed any difference between modes, though haven't checked very close.

When the car is fully loaded (or more, with 5 adults), the extra mass requires more braking force to achieve a given braking rate. This may help put you over the regen-only threshold into friction braking, which I believe to have much less braking 'pause' feel, as described above. LIkewise, "slamming the brakes" should go straight to friction, also producing less 'pause', regardless of load.

I have no feedback with regard to the difference you may feel on the acceleration side.

 

There's no way can "Eco" (or "Power") mode affect the traction available between tires and the pavement.

 

Yes—this is one of the very most-discussed things about owning a Prius. They all have done it, all the way back to Gen 1, and it really isn't anything about ABS being 'pissed off'. It is the car, while braking with regen (meaning only the front wheels) deciding that the traction may be iffy enough that it should switch to the hydraulic brakes, which act on all four wheels, so just by itself gives twice the traction to work with. That transition is not, itself, an activation of ABS, but it is a prerequisite (for ABS to happen, the car has to be braking with the hydraulic brakes), so making the transition brings the car one step closer to being able to go that next step, if necessary (if whatever traction issue was detected isn't already resolved by switching from two braking wheels to four).

The cause isn't always a real road-traction problem (though it can be). It can also just be hitting some bump or pothole so there's a wheel that travels a slightly longer or shorter distance than another one, meaning a difference in wheel speed signals, which is what the ECU uses to judge whether there might be a traction issue.

You really don't have to do anything special about it. Just keep your foot on the brake where it was. If with the slight hiccup it looks like you'll overshoot where you were aiming to stop, just push a bit harder. Because this only happens during light/moderate braking (harder and you'd have been on hydraulics already), there is always plenty more on tap for you just by pushing harder.

The explanation hasn't changed much over the years. A great explanation was given fourteen years ago the first time I asked about it.

 

I'm not recalling anyone else reporting this pattern.

 

Launching from a stop in ECO mode, the engine does speed up more in relation to forward acceleration than in the other modes. That behavior has nothing to do with traction of tires against pavement, but I can imagine in might somehow be perceived as slip. ???

 

It would be interesting to post the ABS/Traction History freeze frames for a few of those incidents, in and out of ECO mode.