ABS light, traction control light, brake light on + no regenerative braking and cruise control

Hello everyone.

I'm a new and (aside from the title) happy 2012 Prius owner. I've always wanted one, and managed to find one at a reasonably low mileage (~125k) and a very good and comprehensive maintenance history in its Carfax from its single owner prior to myself.

I also managed to purchase this thing at a discount, because the (local, non-Toyota) dealership's mechanic was convinced that this particular car needed its entire ABS module replaced at the time of sale. Supposedly the ABS light came on after they already brought it onto the lot and cleaned it and swapped out its oil, and the issue was new and "sometimes turned on, sometimes turned off" when they test drove it themselves. It has since been completely consistent for me. As an aside, the actual day-to-day braking and driving are completely without issue, but my fuel efficiency is definitely taking a hit without the regenerative braking.

I took it, deciding that even if it was the entire module that's at fault, I can ultimately afford the repair anyway, and that the car is otherwise in such good shape that it's a solid worthwhile investment regardless.

However, as the title suggests, all of these OTHER problems are persistent with it as well, which, after researching threads online as well as the owner's manual, make me inclined to believe that it's actually an issue with a wheel speed sensor or some such instead, because that seems more statistically likely to me than all of these systems individually all suddenly being broken in such an otherwise well-maintained and reliable vehicle.

But the second mechanic I took it to late last week also seemed convinced it was the module itself that needed a replacement... and also admitted to me that he didn't know how to fix it anyway. Does anyone here have any advice on what could be leading these two separate mechanics to that conclusion? Why are the codes for the speed sensors being faulty not showing up to them if that's really the issue? Have these two separate mechanics simply not been familiar with how to properly diagnose this problem, or could the problem possibly be elsewhere?

I'm going to be taking it to be looked at by a third mechanic that seems more comfortable with the Prius next week, and I just want advice on what tips I can give him to help him narrow things down.

Thanks in advance to anyone that takes the time to answer my question. I'm becoming very frustrated with this.

 

As an aside, the codes given by the last mechanic are CC1203, C1336, and C1345.