Today the tech said he recently had a 2003 gas model RAM in and two other brands for ABS. Also related that on some new GM 4 wheel drive trucks with the electronic power steering, they are having the steering and brakes malfunction when either hitting a bad bump on a curve or even a staightaway and also when offroading. The steering locks and won't turn for a moment or they cannot get out of a deep rut.. So let's engineer some more problems into our vehicles to satisfy the Gen X buyers or the government. He also said his shop will not ever work on any Land Rover product. Takes four hours to bleed the brakes and the electrical problems are difficult to figure out even with the computers. Don't know if all this is true but he seems honest. So I think you are right to be concerned Seafish.
Re: the question about the speed sensors, we did not mainly because the fault was indicated to be a short in the main box. But it cannot hurt to try that. Maybe one of those sensors shorted and sends a message back to the box. If that turns out to be the case I will update this post again.
I have a 2004 Land Rover, and do all my own work on it. There were some issues with the ABS sensors, but there was a pretty easy fix for that. I also have a special computer tool for the Land Rover that is locked to the VIN that allows my to do computer diagnosis, it's not a CAN system, one of the last years to not be CAN, but it does have a network of sorts. Having said that, to be completely fair, that Land Rover has about 75K miles, my 2009 Dodge Cummins has about 55K miles.. and I'm dealing with more substantial issues on the Dodge right now with an erratic ECU CAN communications on the network.. I already replaced the TIPM, which apparently was not the problem, unless I got a second bad TIPM.. but my point is generally I have not observed the nightmares many report with Land Rovers, but I don't doubt they happen, there are some issues that if not maintained properly can lead to big expensive repairs, but that is not an issue unique to Land Rovers. Many makes and models have things that need attention to prevent bigger issues.
Any 2004 or newer car is going to have some kind of network, and most will be CAN. Also, any ABS car is going to need a computer interface to properly bleed the ABS pump and valve body. It's actually not difficult, but you do need the right tools to do so. The wiTECH micropod 2 that I linked should be able to do a brake bleed procedure. I also recommend getting the factory service manual from FCA Techauthority online, it ships on a CD disk, and is reasonably priced. With that and the proper computer based tools, you should be able to figure this out... that said, given what you have said thus far, that module needs to be rebuilt, or replaced.. and they generally are not cheap. That said, on the Land Rover, I was able to replace the solenoid shuttle valve portion only on the ABS pump/valve body, which was about $50 and it fixed what is commonly known on Land Rover Discovery 2s as the "three amigos" Since the ABS does more than brakes on that car, when there is a problem with the ABS, you get 3 warning lights, ABS, Hill Decent Control, and Traction control, since all use the ABS to function.