Brake Booster Pump Motor running too often and too long after replacement

I believe you're going to find leaks usually are around the accumulator and the pump generally but yes the other part can be suspect many times if you use a mechanic stethoscope and be quiet and listen to the business on shutdown startup brake pedal depressions have someone pressing on the brakes while you're out listening in between all the racket and sometimes you can hear the leak literally and then you kind of know what component you're dealing with so as the part that does not house the pump and that high pressure accumulator is leaking as it leaks down it turns the pump back on and the vicious cycle continues or the leak could just be at the accumulator pump section and it will do the same thing That's why Toyota and lots of places want to replace both parts at the same time and those are going to be about anywhere from 12:00 to $1,800 for the two pieces together there's a wide range of pricing apparently so that's what happens I don't see why you would rebuild the accumulator pump motor only I've taken mine apart just to look at on the generation too not really much to see and the pump doesn't really go bad it's pumping away all the time you hear it It's not pumping away because it can't pump enough pressure where it's pumping the pressure to cannot hold it. So I'm not sure why I would be rebuilding the pump or the motor I'm sorry It's working just fine You hear it.

 

Should be hours without the brake pedal pressed, so that's already awful. There isn't anything else you're waiting for really. As for extra wear on the pump, sure, you can do the math; every day driving around like that can be like a year of normal use.

 

So did you figure out if it was the pump or the actuator that was the problem?

I have the codes c1256 c1252 and c1253, but no c1391. I'm thinking it's only the pump but I'm not certain. I can hear the pump running every few seconds or minutes even without braking. I'm thinking the accumulator in the pump can't hold the pressure rather than the actuator internally leaking.

 

Maybe the accumulator or circuitry is not holding the pressure that the pump is making so it's leaking down internally not outside of the car and the pump has to come on to try and run it back up to spec then it cuts off and the same dance goes over on and on

 

The only thing "accumulator can't hold the pressure" could mean is something leaking away somewhere. If nothing leaked away, the pressure would hold.

Because the two units are piped together, an internal leak in either unit will give you the same symptoms and the same trouble codes. There is no easy way to tell which one is at fault. With a mechanics' stethoscope, if the leakage is fast enough, you might hear a hissing noise louder in one unit than the other, during the quiet times between pump runs.

Which unit it turned out to be in somebody else's car won't matter much to which unit it turns out to be in your car. All that matters is which one it is in your car.

If you can't pin it down with a stethoscope, you can just play the odds. The odds favor it being the top unit in the drawing here (also known as actuator and master cylinder), just because it has many more moving valves inside, so many more ways to get leaky.

 

Didn't see your reply before messaging you. So it seems the most likely culprit is the actuator, but I'm just going to replace both because I don't have the skill set or tools to pinpoint it.

I was wondering if a 2014-15 actuator would work on a 2013 without any firmware issues? From my research there are three different versions 2010-11, 2012-13, and 2014-15. But it seems from what ive been reading the 2012-13 and 2014-15 are interchangeable, but I'm not sure.

 

I couldn't really recommend anything other than matching the part number that autoparts.toyota.com shows for your VIN. Some substitutions might end up working, but that's nothing I could promise.

This is made extra tricky by the fact that these things have easily-readable numbers showing right on them that are not the part number, and a lot of online sellers list that number instead of the actual part number.

If you buy new from a dealer, you should see the right part number on the invoice and on the box. From other suppliers, a bit chancy.

 

So I had the same issue and same codes as you.

I have a 2012 Gen 3 Prius. I ended up replacing just the brake booster first (as that is the part that fails most often)and decided to replace the pump only if it was also faulty but at a later time. Even the TSB for this issue(sorry I don't have a link) states to only replace the booster if the pumps label is oriented a certain way. I paid $620 for the booster at toyota and replaced it myself. I used techstream for the air bleeding and linear offset calibration. All lights went away and my brakes are working as they should.

 

You might be thinking of the D0H recall. That was a different issue. Some 2010s were built with dodgy accumulators, and you could tell which ones those were from the label orientation. I don't think it applies except to that specific issue.

 

So I changed the abs Actuator and the pump stopped coming on every few minutes and the accumulator pressure is holding. However, I still got the codes c1252, C1253, and eventually C1256 and the alarm went off and the pump stopped working. I couldn't get anything to get the car out of failsafe mode, until I wiggled the pump harness connections and the car came out of failsafe and the pump started working. This is the second time I've wiggled the harness connections, first time was a month ago when I first started getting the issues and codes.

I order a pump to replace it, but I'm wondering if I have a bad connection to the pump.

Attached are screenshots of the accumulator pressure for about 4 minutes each with some brake presses where the pressure dips.

 

I have a 2011 Prius with the same code C1252, C1253, C1256 and the pump comes on every 10 secs and I don't remember why I decide to rebuild the brake pump accumulator (found a local electronic shop) but while I am waiting for it and open up the actuator/cylinder master I do see a little oil in the ecu so I am going to get the one online from toyota but the part is is 47050-47140 while my original part is 47210-47310. I am guessing that's why it needs linear offset calibration? I found another post saying even toyota can't calibrate it because the part is different . Just wondering if you had a problem in calibrating it and if techstream from ebay would work? thanks.

 

That's correct part number for the 2011 Prius, the number you have is the mark. Here's the link to the part 47050-47140 where it shows the mark number 47210-47310. I attached a screenshot, I can't post links yet.

Use thinkdiag from Amazon, it's very easy to use, and it does the abs bleeding and linear offset calibration. If you're in southern California I can give it to you.

 

Yes, I am in Garden Grove Southern California. I bought the blueDriver pro but it doesn't seem to the bleed option.