Diagnosis Help??

My 2010 Prius developed an issue recently (I've not had it very long) but my dash lit up with several lights, and my regen went away. Its an ABS issue obviously, so I got the codes pulled with a Techstream. The Techstream gave me code c1391 and said "Abnormal leak at accumulator." So what I'm looking for on here is some help in making sure I'm looking at the right part. The pump buzzes frequently in short intervals. What I'm thinking the code says (and what I'm hearing from the car) seems to indicate that the accumulator/actuator (the part below the actual brake master cylinder) is going bad. Does that seem right to people here? I'm just trying to make sure I know which part(s) to order so that I can fix this issue.

Thanks y'all

 

Ok guys, thanks. The pump is running (when the codes are present) every 10 or 15 seconds. As far as the recall, I checked and I have one that's actually in that freaking 3% that wasn't affected, visually confirmed by the label placement on the accumulator. I wasn't sure what those settings in techstream were going to be doing, so I haven't played with them yet.

 

Yes, when its in ready (or even NOT in ready) no one in it, the pump kicks on roughly every 10 or 15 seconds, while I have the codes cleared (to see if it was just a glitch) it doesn't pulse as often, but when the error code returns it goes back to the same.
When I was sitting in the car, just hooked up to techstream, not doing anything, it does pulse the pump every 10 to 15 seconds.
I can hear a hissing sound, in that area when I lean down to look.

 

That's certainly a tool I'll be picking up tomorrow, just to make sure... If need be I am prepared to replace both, but I'm planning to make sure which it is (or both) before I crank the first wrench, that way I can have all the parts and supplies needed before I begin, so that its a one time teardown. I do have a question, a mechanic friend (he has worked for Ford and Dodge not Toyota) said he thought the part/s might have to be reprogrammed after the new ones get swapped in; any insights on this one?

 

OK... I just got done installing a new Brake Actuator (accumulator was actually ok, you were right, leaking bad at the line that runs to the abs accumulator) but now I've run into a new problem. I'm hoping that its just an ID 10 T error on my part. I reconnected the 12 v battery and then put the hybrid safety plug back in. When I try to start the car it pops up a "Check Hybrid System" message on the display. Any ideas what I might have done that's kicking that error? I'm done for the day (probably tomorrow too with weather) so I'll reconnect everything and check codes with techstream next time I'm out there.

 

Update: It was indeed an ID 10 T error. I forgot to lock the hybrid battery plug in when i put it back. Codes pointed me to the problem. Once I fixed it, the error code cleared and she started right up. Accumulator cycling at the correct intervals now, just have to finish bleeding the brakes and put the wiper assembly back on and she's back up and running. Thanks guys, for all the help in this matter.