If you have the 4.0 engine or 4 wheel drive, you have all wheel ABS brakes. Other models got all wheel ABS in 2001. The possible exception is if you have a late 2000 model, you may have 4 wheel ABS. Manufacturers sometimes introduce some features of the next model year before that model is announced. Look for an exciter ring and sensor on the front brakes. If found, you have 4 wheel ABS.