I have 96k miles on my 05 Prius. I put new pads on the front and figured I might as well bleed the brakes. I used a MityVac and went to each of the calipers and sucked out the fluid. After doing that, I went back to each caliper and had my son press/release the pedal while I opened and closed the valve to let the fluid out. I went through and big bottle of brake fluid doing each wheel making sure I completely flushed the system. Now that I am finished, when I start the car, I notice the ABS light and Brake light is on, the brakes are really soft (to the point of almost not working), and I have a high pitched whine inside the car. I did a couple searches and see that these brakes cant be serviced like a normal car. I see mention of removing relays before doing the bleeding. I didnt do this ahead of time. Now that I have already done this, is there any way to recover from it, or do I have to have it towed to the Toyota dealership and pay them to fix it? Thank you for your help.
Did you at any point let the reservoir get empty? You might now have air trapped in some of the hard-to-get-at parts of the system. . While you'll find a more complete explanation in the service manuals than I'm about to bang in here at the moment, in general you'll want to bleed the rear lines with the system powered up normally and the front ones with the system down and pump relays removed and the whole thing depressurized. A look at the hydraulic diagram should hopefully show you why -- on the fronts you can take advantage of the "backup mode" to go directly from the master cylinder to the front cylinders. . _H*
Normally bleeding is done with the help of a Toyota computer which sequences the valves. It's not the normal shade tree mechanic system used on older cars. As hobbit points out, you can do some bleeding if you know what you are doing, but you have to be careful. Most people should have it done by Toyota. Tom
Oh trust me. I certainly learned a lesson. I just came in from the garage, and wonder if I have the problem fixed. Here is what I did. I jumped the OBD2 pins 4 & 13 and cleared the codes. I then removed the ABS relays, and MityVac'd the front brakes again. I would get a lot of suction on the hose, open the valve and let the fluid/air come out for about 15 seconds, then repeat the procedure 3-4 times. I was seeing a lot of air bubbles coming out, but I am not sure how much was coming from around the bleeder valve threads, and how much from the lines. I think a majority of it was coming from around the threads. I kept the reservoir between the MIN & MAX marks the entire time (even earlier today). After the bleeding was done, I put the ABS relay's back in, then powered the car up and pumped the brakes a few times and held it. Then I powered the car off and back on, pumped the brakes about 20 times then held it for 10-15 seconds. At this point, there was no more light, and the brakes seems to be back to normal. I drove it around the neighborhood and it seems like everything is back to normal. I do hear a rubbing sound which sounds like it is coming from the front, but didnt know if that was the new brakes, or possibly the crap Bridgestone tires I have on it. They are the most noisy tires I have ever heard, and make a lot of road noise. I just cant remember if they made that much noise. This is my wife's DD, so I am not very in touch with the regular noises. I told my wife that I will drive it tomorrow just to make sure everything is fine with it. I dont quite no what to do now. Take it to Toyota and tell them to bleed the brakes anyway, or assume I was able to fix the issue. Thank you for your help.
Hi btrotter. I'd say that if the high pitch whine is gone and the brake pedal now feels good then everything is ok.
If you can drive the car to work and back, then I would assume that you've successfully fixed the brake system. Congratulations, thanks for describing in detail how you implemented Hobbit's suggestion.
I drove the car to work today. About 30 miles on the highway at varying speeds. Everything seems perfectly fine. Brakes stop fine, pedal feel is fine, no more alarms. I remembered that I also rotated the tires yesterday and put the ones with the most tread up front, so think that is causing the noise I am hearing.
Good that you got it fixed. Vacuum bleeding is fraught with a certain amount of peril, as you don't know what else you might be sucking on [heh], and at least at the end of the process you want to make sure you're using *pressure* instead since that's what the system normally handles. Vacuum bleeding is tempting as it's generally a one-person operation, understood, but isn't a cure-all especially for a complex system. . The high-pitched whining is from the linear solenoid valves in the actuator modulating pressure into and out of the wheel lines. If you listen closely you can hear this in a system that doesn't have any air in it; evidently a bit of air lets more of that sound out. . _H*
All I can say is that I learned a lesson. Do my research before attempting any mainteance work on the Prius to see if it is a simple job or not. I have been doing these "basic" and "simple" maintenance jobs myself on various cars for years. So when it is time for new brakes, I just immediately go to the parts store get the stuff and go home and do it, which is what I did with the Prius. I didnt even think to look up in the manual or on this site to see if there were any gotchas with it. There are 2 things next on the list for this car. Flush the coolant and replace the transmission fluid. I guess I will start researching those now before I jump in feet first like I did with the brakes. Thankfully this site exists. Your article on removing the ABS relays and another on clearing the codes through jumping the OBD2 pins is what saved me this time.
I was looking at the pinouts for OBD2, and from what i could find, pin 13 has no connection (4 is chassis ground). Was that a typo, are the pinouts on the Prius different, or am i looking at outdated diagrams? Thanks in advance for any response.
Pin 13 is designated TC and is a real pin. That is connected to the TC terminal on several of the ECUs. I recommend you consult the Electrical Wiring Diagram and other repair manual info for your model year. You can obtain this at techinfo.toyota.com
DON"T FLUSH the coolant! Just Drain and refill (The pressure of a flush can cause harm to the cooling system). Note that you may find it takes several tries to get the air out of the coolant loops (there are two independent loops, one for the ICE and the other for the Inverter). I just let my dealer do it, but others here have been successful DIY. The spec calls for the pink, pre-diluted, Toyota Super Long Life (SLL) coolant (replace every 50k miles after the first change at 100k miles). Don't use the red Toyota Long Life coolant (it will need to be changed on a 30k mile schedule). JeffD
