the abs booster/master cylinder has failed due to an internal leak causing the accumulator pump to constantly run and sets a c1391 dtc. the brakes work poorly and has a stiff pedal feel. braking is definitely reduced. this issues has not been seen by any dealer, shop, or agency yet. I was a toyota certified Master Diagnostic Technician for years before i quit to be a stay-at-home dad and am more than qualified and capable to accurately diagnose this. in addition, toyota has a CSP out (ZGB) that covers this, but the coverage needs to be extended. this is a known very dangerous failure that should be covered for much longer. i did notice, what i thought was an over-frequent cycling of the accumulator pump, but since i had just purchased the vehicle, it was hard to tell how out of the norm it was.