There isn't a scan tool out there that tells you how to repair your vehicle.....all they do is read codes and transmit data......and that is only half the battle....if you don't have an ABS manual with trouble trees, you can't diagnose your problem....there are even instances in the manual, where you need a bidirectional scanner that will command components in the system.....these scanners are very expensive......
However, from experience, as a GM tech, I would say 99% of all ABS problems come down to wheel speed sensors and harnesses......it rare for an ABS module/BPM(modulator that has the solenoids) to have a problem......it can happen but it's rare....on the newer vehicles, the ABS relays are built into the BPMs, and if they fail the whole unit has to be replaced....
The way I repaired ABS problems was, hook up the scan tool, and read the code....by reading the code, you narrow down which wheel circuit or circuits are at fault....it's usually just one, but if you allow things to go too long, other problems can occur and you end up with multiple problems....
Once you know which circuit is the problem, you road test the vehicle and watch the data for that circuit on a scan tool(GM scan tools have the ability to capture data, so that you can not only record it and play it back later, you can also plot it on a graph).....
The easiest to fix are the ones where there is complete circuit failure, in other words, there is no speed signal received......for example, three wheels give speed that match the speedometer.....the 4th, the one with the code reads "zero"......so I go back to the shop, put the car on a lift, rotate the wheel on the bad circuit and look at the scan tool...it reads zero......every tech has an old hub/sensor in their box(one that was replaced because of a bearing noise, but the sensor is ok)....so all i do is disconnect the harness to the sensor on the car and attach it to my test hub....i spin the hub.....I look at the scan tool......if a I get a reading now, I know it's the sensor...if I still get no reading, then I Know it's the harness(broken wire).....
The cars that are problems, are the ones where you go out on a road test, and the circuit that gave the code is working.....this is an intermittant problem....this could be caused by a bad harness that only occurs when the harness moves a certain way.....it could be water intrusion that only happens when it rains....if it doesn't act up, then it comes down to a tech's skill in assessing the answer to the problem.....as I said before, the GM scan tool can plot data.....if I don't see any data problem, then I plot it....then I look at the graph....if lucky, I will see a "blip" in the graph when the problem occured....
Sometimes water intrusion is a problem......if you disconnect the harness from the sensor, and water comes out of the harness when you shake it, in those cases, the sensor and the harness have to be replaced....
So you can see, getting an ABS scan tool for diagnosis, can be very expensive, and is not practical for a DIY'er........sometimes you get lucky with a visual inspection and see a harness broken......sometimes you can get lucky just by checking the ohm output of a sensor, and also the a/c voltage created by rotating the wheel.....but without at least something to read codes, to point you in the direction of which wheel circuit is at fault, there's not much you can do.....