I am going to tack my findings onto the end of this post, it was the most recent one i could find.
I had been throwing ABS VSC fault lights like the OP had.
skiddy car, VSC TRAC, VSC OFF, ABS
for 3-4 months, i decided i would swap out the ABS sensors (i had previously planned to remove the wheels and clean the brakes after the cold weather)
so it was not an extra big deal.
i swapped out the sensors , still had the fault light,
brought a code reader with ABS pulled some codes, it was throwing
C1223 abs control sys malfunction
C1249 open circuit in stop light switch
U0073 control module communication bus off
U0123 lost communication with yaw rate sensor
U0124 lost communication with lateral accel sensor mod
U0126 lost comms with steering angle sensor.
after some further hunting i came up with this brake light switch fault from a couple of forums, swapped it out, job done.
SLA1024 was the switch, that works for runners up to 7/31/2005. after that you need SLA1028.
when i look back at the symptoms, it would usually come on after i hit the brake , it makes sense, but it felt more random, as i rarely hit the brakes sometimes. i need to sharpen my trouble shooting skills. i killed some OEM toyota abs sensors in the process, saving grace was the replacements were cheap.
thanks to all the forum posters for continuing to log faults