Brake assist priming occuring every 15 seconds or so
 

Hi All,

I have a '07 TCH with 109k miles on it.

I recently noticed that when I open the car door to get into the car (with the engine off), the brake assist primes for quite a bit (> 30 seconds). Searching my brain, I recall in the earlier days it would only prime for about 5 seconds).

When I start my car, I notice that the sound can be heard priming the brake (vacuum?) every 15 seconds or so and lasting about 3-5 seconds. It primes every time I release the brake pedal.

No errors are shown on the dash board. I suspect the vacuum tank (if there is one) is leaking, causing it to prime often.

Has anyone had this problem? I am out of warranty and dreading to see what the damage is when I take it to the dealer. I'm hoping it's just a loose screw :)


My apologies if this has been discussed before. I tried searching the forums and couldn't find any relevant threads (could also be because I'm not using the proper search terms).

Re: Brake assist priming occuring every 15 seconds or so
 

That's your brake actuator or accumulator, there's no brake booster (or vacuum in conventional cars) if there are no VSC errors showing up on the dash I guess it's still ok. It might be leaking a little bit (which is a common issue on prius) Others tried to bleed the brakes hoping it will fix the problem. Is the noise louder or just the same but longer?

Re: Brake assist priming occuring every 15 seconds or so
 

Thank you for your reply. The sounds is the same audible level as before. It does get a tad bit louder as it nears the end of the cycle.

What does the accumulator / actuator do? It sounds like an electric pump going on and off.

Re: Brake assist priming occuring every 15 seconds or so
 

it controls the hydraulics (along with the skid control ECU) of your brakes which consists of pump motor, linear solenoid valve, accumulator, wheel cylinder and master cylinder pressure sensors.

Re: Brake assist priming occuring every 15 seconds or so
 

I have exactly the same problem, Toyota says the brake actuator must be replaced, the situation will eventually lead to a brake pump failure, and it is as if you are pressing the brakes every 15 seconds. I suspect the cause is an internal leakage and/or fault in the overpressure relieve valve inside the actuator unit. You can hear this leakage as a hissing noise inside the actuator after priming. Unfortunately the actuator is a sealed unit with pressurized nitrogen and cannot be opened or serviced, this means around $2k or so to solve the issue.:angry:

Re: Brake assist priming occuring every 15 seconds or so
 

I hear you there. My actuator/accumulator would turn on every 5 seconds and I determined it was time to get it fixed. I did not want the actuator failing on the road leaving me without brakes.

When I called my toyota parts store (Frontier Toyota in Santa Clarita, CA), to see how much the part is, the parts mgr. asked me if I got their number online. I did and he initially quoted me $1252. Then he said it would be around $150 to ship. When I told him I was local, he then changed the quote to $1669 (the MSRP). When I asked him about the lower price, he said they had a different website to compete with online retailers, but since I was a local, he could not give it to me for that price.

Long story short, I found the other website he was talking about: http://www.mytoyotapartsstore.com/in...brake+actuator and printed it out and made sure to include the page that stated

"MyToyotaPartsStore.com is the parts department of Frontier Toyota a full service Toyota dealership located in Valencia California."

The service advisor was able to give me that price (without the shipping charge), so total out the door to replace my brake actuator was $1655.63. Here's what they did:

REPLACED ABS ACTUATOR ECU ASSY. AND BLED BRAKING SYSTEM.

PERFORM MULTI-POINT INSPECTION (FREE) FRONT BRAKES _8MM___ REAR BRAKES_4.5MM_____ TIRE PSI32________

CUSTOMER STATES INSPECT BRAKE ACTUATOR MAKING LOUD BUZZING NOISE/INSPECT AND ADVISE. NOISE WAS VERIFY BY SHOPFORMAN IT WAS ALSO VERIFY BY TECH SEEM LIKE BK ACTUATOR ITS DICHARING BY ITSELF.AS 1ST SPEP WILL BE R/R ACTUTOR AND BLEED SYST , NO EXTERNAL BK FLUID LEAK.

On a side note, after 110k miles it's almost time to replace my rear brake pads. This will be the first time since I bought the car it will be done. The front pads are still in good shape.

Good luck! At the very least, you could buy the part and have your dealer install it and save about a hundred bucks or so.

Re: Brake assist priming occuring every 15 seconds or so
 

I'm confused. Is there supposed to be a noise? How often should you hear the noise? I hear mine rather consistently when starting the car, baking, and when I shut the car off. If it is a problem I'd like to get it fixed before the extended warranty is up.

Re: Brake assist priming occuring every 15 seconds or so
 

This seriously bugs me. I just bought a 2007 Camry with 30K and is still under the 60K powertrain warranty until July 2012 but to hear of such premature failure of a brake system is absurd! Where is the Toyota quality that I paid premium for?? Now they expect us to fork out $3000.00 to replace this unit?

I've been a proud owner of many Toyotas in the past but now I'm really questioning why??

So who wants to join ranks and bring this up to Toyota??? I'm sure we can gather many Prius owners who are forking out money to repair this "brake accumulator" issue. How about those whose emptied their pockets to patch the issue? Wouldn't you like some compensation??

I'd like to get something done about this but need your help to figure out where to begin.

Re: Brake assist priming occuring every 15 seconds or so
 

I guess the fist step would be to figure out what "normal operation" is. I haven't' found anything clear on that yet. I'm going to search alldata and see if I can find anything. Maybe someone that knows how this system is "supposed" to work can chime in.

Re: Brake assist priming occuring every 15 seconds or so
 

Well. As far as I understand from other members, the a slow leak will cause the accumulator to pump more frequently and eventually throwing codes and then eventually complete loss of brake pressure altogether.

Re: Brake assist priming occuring every 15 seconds or so
 

I think my 2007 with 68k is experiencing the same thing. I hear the noise much more often than I have in the past, every 15-30 seconds while driving at low speeds around town. I have an extended warranty that is good until August of 2013, but I might be bringing it in to have them check it out before it triggers warning lights. I'd hate to have it go out on a trip.

Re: Brake assist priming occuring every 15 seconds or so
 

Well crap. This JUST started happening on my 07 a couple of weeks ago. I notice it one day when driving home from work. It was a nice day so I had the windows down and from the time I entered my neighborhood to the time I got to my house (about 1 mile) I heard this noise every few seconds. This is NOT good. As has been stated over and over again, this is not the kind of quality (or lack there of) that I expect from toyota.

Re: Brake assist priming occuring every 15 seconds or so
 

This started happening to my 2007 Camry Hybrid too recently. The car has only 42K miles and I started hearing the more frequent noise coming off the ABS pump, specially when the car is idle and most recently I hear a different noise when I fully press the brake pedal. I took to my dealer last week and was told I need to replace the "Actuator Assy, BR" part "44050-30300". They quoted me $2,629 but told me the would give me a 25% discount and quoted $560 for labor. I know I can get it online for much less so I'm not even worried about their quote.

This does not affect the brakes function but can eventually fail and the ABS won't work. I do agree this seems like a premature failure not typical of a Toyota and I even read they redesigned this pump in newer models as they knew about the failure so I'm thinking it is at least worth writing Toyota a letter and see what they come back with. :angry:

I read in another place recommendations to be buy it used and even DIY install it. I'll weigh my options when it actually fails as I'm not ready to spend $2k to repair it.

Re: Brake assist priming occuring every 15 seconds or so
 

I have a 07 TCH and get the same every 15 seconds noise starting with when I first open my door. It started after about the second oil change but I remember the dealer saying it was okay. The noise became louder more recently so I took it to the dealer this week out of warranty and they told me that this was a normal sound and nothing was wrong. Well I told them that the unit sprayed some fluid up towards the underside of the hood. I showed them where the stain was from the brakes and when I got my car back the next day they steam cleaned the leaking break fluid and the pretty much the entire engine. I was really confused when they told me the sound was normal. The reason they kept my car overnight was to fix a bad water pump and change fluids.

Toyota needs to recall and fix our problems breaks.

Re: Brake assist priming occuring every 15 seconds or so
 

My 2007 TCH when rather new would pump up the ABS for 5 to 10 seconds. After 5 years of driving it still happened about the same length of time.

Before I traded my car I dropped by the dealer and had their certified toyota tech to look at my liquids. He added a little brake fluid which was mounted on the firewall. He also added about a inch of pink coolant to the reservoir and just a little to the inverter bottle. I had been keeping a eye on the liquids monthly for all those years. The car only had 38000 miles on it when I traded for the '12 TCH.

Re: Brake assist priming occuring every 15 seconds or so
 

Sorry to add to a two-year-old post.

I noticed this problem with my 2007 TCH for over a year now and the dealer said that it's normal. However, I was driving to work today, going about 70 mph when an idiot changes lanes right in front of me trying to exit the freeway at the last second. I go to slam my brakes and the Check VSC System goes off. The dash lights up like a Christmas tree and I realize the brakes don't work at all. I go into a panic for a second or two thinking about throwing the car in neutral and hitting the parking brakes, but just like that the dash lights go off and the brakes work again. It's like nothing ever happened and the car drove fine the rest of the way to work.

This is scary. The TCH is usually my wife's commuter but since she has the day after Christmas off and I don't, I decided to save a few bucks in gas and go with the TCH. She's not as mechanically inclined as I am and I don't know what would have happened if she were behind the wheel in a situation like this.


Maybe it's cheaper for Toyota to pay a million or two if somebody dies in a situation like this than to recall all the cars and pay hundred of millions to fix the problem (if there is a fix). Toyota needs to come clean and take care of this problem, not to mention the water pump problem they have also.

Re: Brake assist priming occuring every 15 seconds or so
 

Wow! That is a harrowing story... You should contact the NHTSA immediately about that!

Here is some more reading that you might be interested in over on TN:

http://www.toyotanation.com/forum/10...ode-c1391.html

Re: Brake assist priming occuring every 15 seconds or so
 

Too bad about these actuators failing. It would be nice to know updates from some of the users who posted on this thread a few years back if they still have the same situation or something did fail?

Re: Brake assist priming occuring every 15 seconds or so
 

Hi All,

I've replaced the brake actuator assembly back in 2012 and so far so good (knocking on wood).

Just to clarify the issue:

1) Hearing the pumping/vibrating sound when you first open the driver car door is normal. This is the actuator putting pressure on the brake system. Opening any passenger door will not activate it.

Hearing it again after pressing the brakes is also normal, as it replaces the pressure on the system.

It is normal to NOT hear the sound when you first open the driver car door shortly after you just closed it (as the pressure on the lines are still within the targeted pressure).

It is also normal to NOT hear the sound during light braking, as the pressure on the lines is still within the threshold.

If you are unsure what the sound is, get in your vehicle, start it up and wait for the engine to turn off (I know, I know, waste of gas, but it's for experience sake ;) ) When it's nice and quiet, slowly step on the brake pedal down, perhaps as far as it can go, hold it for a few seconds, then lift it up. You should hear the brake actuator turn on and apply pressure to the line. If you don't hear it, slow step on the brakes again and let go. Eventually it will turn on. It sounds like something vibrating more so then something pumping.

2) What the issue is, after the initial pressurization of the lines (when you open the DRIVER car door), after some (short) amount of time, you hear the brake actuator activate. By short I mean maybe 15-20 seconds or shorter. This happens without stepping on the brakes or doing something that would normally depressurize the lines. With my issue, it noticed it stuck in traffic, crawling along at 10-15mph with the windows down. I heard the sound go on every 15 seconds, with no usage of the brakes. Eventually the "cycle" started to repeat itself every 5 seconds and so I had it replaced.

A few months ago I had gone to Target (before the big credit/debit card debacle) and parked next to another TCH. There were people hanging out in the car and the car was on. I could hear the brake actuator turning on every 5-7 seconds. Their car was parked mind you, so it was exhibiting the problem.

So that's my update. Happy new year to all you guys and gals!

[disclaimer: The information provided above is from my own personal observations. If I used a term incorrectly I apologize. I initially though the brake actuator was a vacuum pump to aid in "power brakes". But after looking through forums and talking with the tech at the dealership, I discovered it puts pressure on the brake lines]

Re: Brake assist priming occuring every 15 seconds or so
 

Really appreciate this detailed message Chris. Thanks a lot.

Re: Brake assist priming occuring every 15 seconds or so
 

Welp.... I think I am finally experiencing this problem. It started yesterday after a lady pulled out in front of me on I-95 during a severe thunderstorm and pouring down rain. I had to slam on the brakes to avoid running into her. I could not tell.... But, I am sure that the VSC system activated.

Before I would hear the system prime for about 5 seconds as I approached the car and would not notice it again until the next time I drove the car or the following day. NOW, I went out into the garage this morning and it primed for a good 10 seconds, then it did it in three 5 second bursts after that. Also, with the car on, every time I press and release the brakes, I can hear the pump run. Before, it was not doing this.

Is the dealer "the only place to buy this part"?


Edit: Ok, I found the new part online for under $1,000 and went ahead and ordered it. Looks like I will be R&R'ing it next week and going to the dealer for the bleed. I am also able to feel the pedal rise (never happened before).

Re: Brake assist priming occuring every 15 seconds or so
 

Looking forward to your report after the part is replaced. I've been living with this issue for too long and if the part is now available for less than $1000 somewhere it may finally be time to get it fixed too! Thank you!

Re: Brake assist priming occuring every 15 seconds or so
 

Absolutely! No problem... I followed this a while back and was so happy to not have these symptoms. I knew when I went out into the garage Sunday, I was in trouble! The stupid thing was priming non stop! Even with the key in the house.

I searched for this part months ago (just for fun) and had a hard time finding one. The cheapest ones I found were $2100 and $2200. Searching yesterday was a little different or I just got lucky. Frontier Toyota Parts CA had 2 of them left, new and in the box. It is the new part # and they were only $953 before shipping. The total was $1,012 shipped.

I plan to R&R myself and take it to the dealer for bleeding and have them replace my sunvisors and get that drivers door window switch greased.

I drove the car today without incident. But, I can feel the pedal rising and falling. It is never in the position you expect it to be.

Re: Brake assist priming occuring every 15 seconds or so
 

One thing to consider is that the brake actuator assembly was redesigned at some point to improve the high failure rate of the original piece of equipment. Do you know if the replacement part you bought is a redesigned unit or of the original design? It may not make any difference if you are not planning to keep the car for another 50K or more miles -- or at this price point it may be worth taking the gamble -- but if it is an original design it will likely fail again eventually.

Re: Brake assist priming occuring every 15 seconds or so
 

Yes... As mentioned above in post #23, it is the NEW part #.

Re: Brake assist priming occuring every 15 seconds or so
 

Ok fellas... I got some more info. on this part for you. Mine came today and it is the real deal, brand new in the original box and packaging for $953. It was $1012 delivered from Frontier Toyota in Valencia CA. Why some dealers are "gouging" the public on the part cost and some are not is a mystery?

Anyway, the box is branded with the new part # and was previously opened. I questioned as to why it had been opened and they said; "it was for more packing material". Good enough.... Then I questioned as to why the part # "in" the box did not match the part # "on" the box and they said; "Individual component numbers on the part itself will not match what is on the box".

This all sounded fishy to me! So, I hopped in the car and rode down to my local "rip off" Toyota Dealer. I went to the parts counter and asked if they had the brake actuator with the new part # in stock. They did! So, I asked if I could have a look at it and asked for a price on the part. He pulled the part off the shelf. It was a sealed brand new un-opened box with the new correct part number on the box. We opened it together and found the same part # on this as the one that was mailed to me! I was very relieved to find that this was legit and I was in fact not "ripped off". This particular dealer wanted $2,566 for just the part. The parts manager took me to a service writer and quoted me a price of $589 to install the new part and bleed the system for a grand total of $3,155!!

Long story short is that nothing as it seems when it comes to this particular fiasco and having to deal with it.

Also, for future reference, the new part # you will need for all of this will be; part # 44050-30660 (this will be the part # on the box) Mine and the box that was opened at the local dealer had part # 44510-30290 (inside the box).

These new units have had whatever flaw corrected and will not fail in the same way according to both dealers.

I plan to install this thing sometime next week and take it to the dealer to have the system bled.

Re: Brake assist priming occuring every 15 seconds or so
 

Hi LS - update us when you have new part in.