ABS Accumulator keeps leaking (C1391)

welcome!
i have no idea, but i'm wondering, are these new oem units?

 

I think there is a new warranty extension on these.

edit: refer to warranty campaign ZJB:

https://attachments.priuschat.com/attachment-files/2019/03/162715_ZJB_Phase_2_.pdf

Booster and Booster Pump have a warranty extension until 8/31/21 with no mileage limitation. A c1391 is one of the eligible fault codes.

 

Was the par replaced a new one, or used?
Two logical reasons why you're having this problem might be that the part your replaced, is/was also defective.
Secondly, might be a wiring harness issue on the abs pump connector area.
Thirdly, were you the one that replaced the part, or a dealer?
Was the abs system bled of air from the system, and the codes cleared, after the install?

 

Yes, absolutely! The accumulator and the actuator are separate units in Gen 3. The accumulator pumps up and stores pressurized fluid, but almost all of the valves and passages through which it could be leaking down are located in the actuator, not the accumulator. Both parts are expensive enough that there's generally a strong incentive to try to pin down which one is at fault in a particular case before busting out the wrenches.

That requires some human detective work. The ECU can give you the code saying "hey, the accumulator pressure isn't holding up" but it has no way to gather enough information to tell you why.

After six accumulators, a case could be made that it's probably the actuator in this instance.

 

Albert Einstein is widely credited with saying, “The definition of insanity is doing the same thing over and over again, but expecting different results.

 

Still hasn't made him the one who said it, though.

 

I'm purchasing an accumulator soon. Is there an easy way to bleed it or do I need special software?

 

Some useful information here:
Scan Tool for ABS/Actuator and Brake Bleed | PriusChat