Brake "Honking" Noise - Bad Actuator Help please

Customer Support Program ZJB Phase 2, if I'm not mistaken, covers 2010–2015, as long as you are within ten years of the date of first use, and under 150,000 miles.

 

Look, what caused these expensive failures is not the nitrogen leaking out, is that something breaks inside the brake fluid lines in the brake actuator, the one that has the ABS integrated into it, the leak caused the fluid to flow back into the reservoir somehow, that is not supposed to happen regardless if there is nitrogen or not, nitrogen is there to help reach pressure faster, not to hold the fluid into place. Maybe a valve fails, a line breaks inside, i do not know because i have never opened one. Fix My Prius could replace his if he wants now, before his pump starts to run more until it runs so much that it burns.

 

I agree that it's more commonly the internal leakage of fluid.

Failures associated with loss of nitrogen are a different failure mechanism—not to be confused with the internal fluid leakage, but simply to be understood as another independent way the system can fail.

When nitrogen leaks from the accumulator, two things happen: (1) you have less of it in the accumulator, where it belongs, and (2) you have some of it in the brake fluid, where it doesn't belong. You can fix (2) by going through a brake bleed (and lo and behold, bubbles come out of a system that had never been opened to let air in). That, of course, doesn't fix (1), but (1) doesn't have very noticeable effects until quite a lot of the charge has been lost.

The effect (2) is noticeable for making honk noises, and is probably a factor in the rarely (but not never) reported "floored pedal no stoppie" failure mode.

 

This is a graph of the ABS modulator function. I need to replace it; just wish I didn’t have to.

Within the past two months, I’ve done so much work to this car for someone who is not a mechanic (a car that has 420,000 miles on it). I replaced the old HV battery cells with new Nexcell lithium cells, cleaned the EGR valve and intake manifold, replaced spark plugs and ignition coils, replaced shocks and struts, and cleaned the fuel injectors. Now I have codes B1442 and B1443 - though climate control actuators seem to be working fine. Do I really want to replace the ABS modulator on a car that has 420,000 miles on it? I’ve never bled brakes in my life (though I bought the Launch X431 Elite with good intentions), let alone replaced a Prius ABS modulator, but why stop now?