Abs
G'day Mate,
This is a common problem on Disco's. The ABS system on these cars is very sensitive and ANY problem will bring the ABS warning light on.
1, Check all the fuses (Not just the ABS fuses but all of them,)
2, Check the brake/stop switch and make sure it is working, if not check to see if its getting power.
3, Check the sensors on the wheel hubs, MAKE sure that they are firmly seated in the hubs and not loose. While you are there, check for any play in the bearings, this can affect the sensor rings.
4, Get an Ohmmeter and check for continuity on ALL of the sensors, there are 4 but the rears are linked ( the readings should be around 1000 ohms)
If all of these check out then, sadly its dealer time. A magic black box is needed to get the fault codes. I had some big headaches with my D1, Did everything but check the brake/stop light switch and sure enough that was the fault. Once it was replaced the fault went away but the car still needed the magic box treatment for the light to go out. I know that if the sensors are loose the ABS light comes on intermittantly, pushing them firmly in will fix it and the light will go off once you get over 5mph.
This is just a an idea as to what to do, these systems are really sensitive and there have been some real horror stories on this website.
Good luck Mate.
Wes DownUnder