2013 Prius - C1391 Code Abnormal Leak in Accumulator

There was a recall on this a few years back, for sure check with a dealership if you haven't already: it "may" be covered.

 

@ChapmanF I think know the ins-and-outs regarding 3rd brake recalls and Technical Service Bulletins. I do know ours was in a few years back for a recall on the brake. There's two gizmos, one more visible near the top, and another further down the firewall. I will not attempt to name them, lol.

I guess what I'm saying: the "goodwill" might actually be an obligation, that they've acknowledged those components are failure prone.

Most recently I got this, albeit from Toyota Canada:

 

Well, everything in a car is failure prone. I think it's pretty commendable, how many times I've seen Toyota come through and say "we know, it sucks when this part wears out, and so we'll extend our commitment to replace it up to seven years longer and over a hundred thousand miles farther than we ever advertised as the new-car warranty".

I even benefited from that in my Gen 1 ... I bought a seven-year-old, 125,000 mile car, knowing I was taking it on completely out of warranty, and four years after that, at 193,532 miles, over 150,000 miles past the end of warranty, I had a car that steered like a brand new one again, because of the steering gear warranty extension.

Was there more to that announcement, a second page that described the particular symptoms or conditions necessary for it to apply? That's the info that would really help.

A quick skim of the front page looks like it applies to the "Brake Booster Assembly". Strictly, when that phrase appears without the word "pump", it means the gizmo that is more visible near the top (which you'll find in the parts catalog with a name like BRAKE BOOSTER ASSEMBLY WITH MASTER CYLINDER, only inside-out and with commas).

If it had the word "pump", then it would mean the other gizmo further down the firewall, the BRAKE BOOSTER PUMP ASSEMBLY WITH ACCUMULATOR, INSIDE-OUT WITH COMMAS.

The OP's trouble code refers (by fortune cookie) to the second gizmo, which is not the one named in that announcement. However (another comma!), an "abnormal leak" that affects gizmo 2 can easily be happening in gizmo 1 really, where most of the valves are. So this is a case for not jumping to conclusions from the fortune cookie, but really following the workup in the manual to pin down where the leak is. (Or, just let Toyota fix it, if it falls under their extended warranty conditions).

-Chap