Strange how there is all this hype about SBC, and we are continually told just how reliable Toyota\Lexus are..
I am always interested to read about problems with SBC as my wife drives a vehicle fitted with this system.
What I continually find though is mostly rumour and gossip but I do uncover the odd snippet that I was not aware of and I have just found this on a US site:
From Consumer Reports Car recalls.
'97 Lexus ES300, Toyota Avalon, and Toyota Camry
In extreme cold, icing could disable brakes' power assist. Brakes would then require more distance and much greater pedal pressure to stop car.
Models: 18,746 cars made 7/96-2/97 and originally sold or currently registered in Alaska, Colo., Idaho, Ill., Iowa, Kan., Me., Mich., Minn., Mont., Neb., Nev., N.H., N.Y., N.D., S.D., Vt., Wisc., and Wyo.
What to do: Have dealer install redesigned brake vacuum hose. Owners of cars in other states who drive in extremely cold weather should also ask dealer for redesigned hose.
These are 'old' cars but I cannot recall reading anything about this problem?
Here on the English Riviera we do not have cold weather

so we're alright and I suppose there just might be different hose pipes used in North America?
Regards
John