This is a problem with the ABS applying itself prematurely. From my personal experience with this vehicle
this could happen for a few reasons.
- One of the wheel ABS speed sensors are Bad and providing a false reading that the car is about to skid before a complete stop and therefore actives the ABS. ( that's the pushing back of the pedal that you feel at slow speeds just before a FULL STOP).
- Its can be also cause by the gear that the sensor is reading or getting its signal from, (this gear is on the Axles and its goes in to the Hubs).
This can also because
by the ABS unit itself
that's malfunctioning and in my opinion should be under warranty from TOYOTA.
In my experience in my shop it was the ABS unit once and the ABS sensor about 3 times.
Here is mu suggestion have this vehicle hooked up to a SNAP
-ON scanner with ABS program and drive ON LIVE DATA while driving look at wheel speeds coming from ABS/speed sensors on wheels. They should all be the same. Try to duplicate problem(hitting bumps on brakes etc) At this time if there is a problem with the sensor it should show a different speed and it will activate ABS. If then works out then you have found the source
of the problem and you can make necessary
repairs. Good Luck and contact if you need more help, Thanks for using FIX YA