Brake actuator failure?

Found your problem.

Not all scan tools are created equal.

They can all read the basic engine codes from a Prius, but most of them are not set up to ask the other computers in the car what they might have to say.

Fortunately, Toyota has built a code reader right into the car specifically for ABS, traction control and general brake code access. You can use this thread to learn the blink code and figure out what the car is trying to tell you. It is specific to those systems, so it can't tell you about engine or hybrid battery stuff. I would suggest buying a better diagnostic scanner if you're going to keep this car longer.

I recently invested in an Autel 2500E for under $70 and it really helped me with a wheel bearing issue.

Using that built in blink code scanner will at least help narrow down what might be done for a fix.

There might not be a cheap fix to your problem, but at least you won't waste money on diagnostics that you could have done yourself for free.

 

The autel can scan the brake codes yes. It is a bluetooth gadget that works in conjunction with an app on your phone.

But what you might have missed is that you can scan the brake codes directly, right now, with nothing more than a paper clip and a steady hand. (It would help to record video of the blinking light on your phone though)

Go read that thread about blink code.

 

I read elsewhere that the 2500E is a no-go for bi-directional processes like brake bleeding, but Autel has other hardware models that share the same smartphone app that do have that function.

 

Same thing happened to me. I replaced the brake pump first, and the leak was still there. I had to replace the brake booster assembly, then it was fixed. The lead originates in the brake booster assembly, replacing it will obviously fix the issue. The reason why Toyota recommends replacing both is probably because the pump might have been running constantly that has sustained some damage.

 

Either unit can be the source of an internal leak. The pump/accumulator unit does contain a relief valve and a path back to the reservoir.

It's just that the booster/actuator has a lot more valves in it, so if you don't know which one is at fault but you're ok with playing the odds, the odds favor it being the booster/actuator.

If your leak is far enough advanced for hissing to be heard, sometimes you can use a mechanics' stethoscope to pin down where you're hearing it.

 

There are many slightly different versions of these items and interchangeability is quite poor.

Even the same body style of the car got slightly different parts to account for different wheel sizes on certain trims in addition to technical and manufacturing updates that occurred through production.

I would suggest looking for what you need through car-part.com. That's a shared database between a bunch of junkyards.

Stay very far away from eBay.

Most of the ones sold there are mis-identified, the seller doesn't even know which version they've got. And lately the parts themselves are pulled off high mile cars and they won't be in any better shape than what you've got now. Worst of all, it's a huge pain to return.

When you use a directory like car-part, you just get forwarded to an independent parts recycler which is hopefully in your city. They may be junkyards, but at least they are professionals. You can work with them directly to make certain it is the right version before you pay money, and if something is wrong you know right where to go.

Ideally you are looking for one that came off a 2012 Prius c that got totaled 10 years ago, so the part is still relatively unused. See how close to that you can get.

 

Yes that doesn't surprise me. At a certain point, autoparts professionals stop trusting the granularity of the database directly. I'd encourage you to search there and look for search results that say "prius c" in the comments or have an obvious picture of a c attached.

Also worth calling them and verifying actual part numbers. Unfortunately a lot of good used auto parts aren't directly web-searchable; gotta do it the old ways.

eBay is okay as long as you are the knowledgeable professional who knows exactly what is being bought/sold and are willing to take the risks.

Not a good setup for first time/occasional shade tree mechanics, and now it's getting gamed all the time.

 

Also, often sellers on eBay will look on the part for some number like nnnnn-nnnnn and put that in the listing as the part number. But Toyota parts often have such a number stamped on them that isn't the actual part number—and often, too, the actual part number that you use to order the part, and you see on the box, is not anywhere on the part itself.

Sometimes if you have access to a part that you know is the right part number, you can look and see what non-part-number number is stamped on it, and then you can recognize that when you see it mistakenly used online. A bit of caution may be in order, though, as sometimes the same non-part-number number (which could be an internal part number of some subcomponent that happens to face outward where you can see it) might be common to more than one assembled part.