abs engages when accelerating on 2003 toyota highlander

Hello, You likely have a bad wheel speed sensor, or the sensors ring may just need to be cleaned. The ABS thinks that one or more of the wheels are locking up, so it restricts engine performance. The other thing is that one of the wheels may be locking up, which would suggest a bad caliper. You would probably notice the sound of a dragging tire if that was the case, and the smell of brakes would be evident on one corner of the vehicle after a long drive.