Break Failure Stop safetly P0571 - my repair done nothing

[leyus]

I get Break failure stop safely notice with ABS light on.

Breaks keep working
Cruise control keeps working.
If I stop and turn off engine it goes away instantly
It comes up entirely randomly, I commute 60 miles one way sometimes both ways nothing, sometimes few miles and comes up.

I tried:
Replaced break pedal position sensor (used one from scrapyard). Still the same.
Replaced break light switch - new one from ebay still the same
Cleaned with contact cleaner break pedal position sensor connector and wrapped cables around it with electric tape -no change
Took it to my car mechanic he could not reconstruct this error, he claims he only 0074 error and he thought it was abs pump or ecu but previous owner regenerated those and provided me reference number for work done with lifetime warranty, so I am unsure of this diagnosis.

Patient is 2003 D5 V70. Any advice what to check and what else can I do will be appreciated. Is it possible that break pedal position sensor from scrapyard was simply bad and im looking in wrong direction ?