2016 Inst. Panel Flashing Triangle & PCS, ABS illuminated

2016, Prius 3 Touring, 44K .
After driving the previous day, this morning the yellow ALERT triangle and PCS warning light are flashing and ABS warn light is on. Dynamic Cruise Control is inop. Car drives fine but ABS is not working-rear wheels lock up on hard braking. Turned off PCS but it still flashes showing "Off". Annoying.
Tried using my $20 OBD II scanner and no codes found. But I think it only reads ICE codes. Pulled front wheels, removed and blew off ABS sensors and mounting holes. Rears appear to be inaccessible...molded wire plug goes into receptacle on a sealed cover. No apparent damage. Checked all fuses that had "ABS" in the application box of Toyota repair manual (not 'owners' manual).
Is a scan at the dealer next? Or do well equipped independents have the necessary equip/software?
Please make recommendations for affordable DIY scanner that works for Gen 4's.

Thanks,
John

 

Thanks to all contributors.
Elektro... thanks for spelling out the components of DIY diagnostics. W7 laptops are cheap and coupled with Tactrix, the hardware is about $250. Considering what diagnostic time costs, less than 2 diagnoses and it's paid for

But... this time, I'm going to have to bite the bullet and take my car to a shop. Need it for Thanksgiving travel and can't manage the logistics of assembling hardware, doing a diagnosis, locating/purchasing parts and doing the repair. But I will report back to this thread with the upshot of diagnosis. Saw another post that experienced a similar problem.

Thanks(giving) to all,
John