Brake failure in very cold weather

i understand used Brake Actuators are cheap on ebay. if this is the only problem in 194,000 miles, not bad.
BTW, you posted in the wrong forum.

 

There are smart things you could do, like reading the brake trouble codes yourself, and following through the troubleshooting steps in the manual for them yourself. Nobody could blame you for checking the facts yourself before taking the dealer's word on a $3.7k repair.

If the facts point to the actuator, nobody could say you weren't smart if you checked for less expensive sourcing options.

If the facts point to the actuator, the system is sounding the alarm for you (not even all brake problems do that), and you decide to ditz around with the brake fluid or battery because you don't want the facts to be what the facts are ... that, I'm afraid, could be called not smart.

It would certainly be called not smart by the other party's lawyer if an accident occurred, which could develop into a pretty bad day.

-Chap

 

There is your answer: you never ever changed the brake fluid on your 194k mile car.

Brake fluid should be changed every 30k miles or 3 years. (Approx). I am sure a person can get away and go beyond those intervals, but you are way beyond that time frame.

Whatever sensitive component the fluid came in contact with in that 194k miles/time frame is probably "fooked".

Your brakes are unresponsive partially because you have moisture in your brake fluid that is frozen.






iPhone ?

 

Is there a supplement I can take that will make me that sure I know what somebody else's problem is, 2000 miles away by reading one forum post?

The hard-pedal symptom is consistent with loss of boost pressure, which is consistent with the audible alarm and (IIRC) the C1256 code. The meaning of "high resistance at pins 1&2" I can't interpret from here because I've never downloaded a Gen 3 repair manual or wiring diagram, but if it were my car I'd sure be over at techinfo.toyota.com doing that. Maybe that would turn out to be consistent with "frozen moisture in the brake fluid", but I'd kind of have to know what pins 1&2 connect to on a Gen 3 actuator to be sure.

A long-time PriusChat contributor, hobbit, did some interesting work with old Prius brake fluid and test strips, and some follow-on research, some years ago. He was surprised at how little the fluid had degraded, compared to other cars.

-Chap

 

Very interesting. Any clue why? I'd suppose the tendency of atmospheric moisture to permeate through hoses and seals would be about the same as on other cars.

 

my guess would be minimal brake pads wear. as they wear little, fluid level stays unchanged and little (humid) air enters the fluid container.

 

I would hate to spoil the ending ... the story starts about 1/3 of the way down the page.

100K maint - 1

-Chap

 

Thank you Chapman for linking the above. I read this quite a while back, but had forgotten what hobbit had wrote. I won't say anything else. Anything else will spoil the ending

 

Also, how is the car parked? Outside or garaged?

Since moisture gets into brake lines over time (which is why you flush brake fluid every few years), I'd not be surprised that the high-tech brake systems would register a "fault" under such situations.

 

As a rule, brake fluid should be flushed every 3 or so years...depending on application and humidity. If you pay attention, you'll notice a decrease in braking effectiveness, and that may be a sign it's due.

 

The Canadian Schedule calls for brake fluid changes. I thought it was just a recently adapted policy, maybe starting in 2014, but had a second look at my 2010 maintenance booklet, see it's buried in there too, albeit with slightly different interval.

Canadian 2010 Prius Owner's Manual Supplement. Note, this schedule covers all Toyota vehicles, so is a real mish-mash of qualifiers and provisos:



Canadian 2014 Prius Owner's Manual Supplement. Still encompasses all Toyota vehicles, but now a complete schedule in handy table format. Much easier read than the US schedule:



I'm not sure about the US schedule: last time I looked, when I made up a spreadsheet version of it, don't think there was mention of brake fluid change.