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Rear Brake Problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Michelbanjolo, Feb 13, 2024.

  1. Michelbanjolo

    Michelbanjolo New Member

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    Longtime lurker, first time poster.

    In December the ABS VSC etc lights came on. There was a long list of ABS codes and after various reading, it seemed like the actuator needed replacing. (The clicking of the actuator was on about half the time, by then.) I salvaged the part and put it in. After the paperclip in the OBD plug trick, the ABS codes were cleared until not much later the lights came back on, now with the code C1343 (Right Rear Malfunction). This code had not appeared before, so even though all the other moles got whacked, this one popped up afterwards.

    I've inspected inside the drum and everything looks in order. When I've bled the brakes, hardly any fluid wants to come out of the RR valve. Whenever I do the paperclip thing (I think the technical term is an "initialization and calibration of the solenoid valve") it will turn off the lights, one time for as far as about 10 miles, then they'll turn back on. After some recent tests, the car or engine or something will occasionally shudder and shake when accelerating.

    I just got Techstream set up and was looking at the data and I can see that the voltage for the RR wheel sensor(?) doesn't get affected by pressing the brakes. The others are around 0.45V and then when I press it there'll be more than a volt in the other three wheels, but the RR voltage won't go up. However, when I reset the solenoid again (paperclip thing), the RR starts responding to pressing the pedal like the others with nearly identical voltages to RL. After braking somewhat hard before a stoplight, the ABS lights came on again and the shuddering started again.

    The shuddering came fairly recently. There's no codes or triangle of death associated with it as far as I can see. It started happening fairly recently. I did replace the brake pads because I was already doing it with our other car. Maybe I did something weird then?

    I'm not sure if this is a problem with the salvaged actuator, the brake line, the sensor, or what. Any thoughts?

    My wife and I have another car so this one has been mostly sitting there as I've tried to solve the problem.

    In summary, what I think I know is:
    1) There was almost certainly an actuator problem causing all of the lights and replacing the old actuator made the old codes go away.
    2) There isn't pressure getting to the RR brake, based on the facts that the sensor isn't registering much and not much bleeds out.
    3) I don't think the shuddering is from tire misalignment as it's very unpredictable even based on speed, except it seems to happen almost exclusively when accelerating.

    The two problems:
    1) Why is C1343 triggering?
    2) What is the shuddering?

    Any insight helps. Thank you!
     
  2. dolj

    dolj Senior Member

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    As you've just got Techstream up and running, I presume you used some other method to bleed the brake system after replacing the brake actuator/accumulator.

    Clear all codes and then run a full brake bleed using Techstream. Make sure to attach a battery charger to the 12 V in order to complete the bleed without any interruption because the 12 V ran flat.

    Report how this goes.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Yeah run the bleed situation and text dream as the actuator has been replaced see if the linear solenoid valve does not need to be reset it'll tell you if it does and see what happens there I've never seen the fluid not come out the rear brake either side I have four of these generation twos here and can walk out to any of them and have my other half sit in the seat push on the brake crack the rear zerk whichever one and fluid will come flying out of there under pump pressure and you can hear a pump running both sides so either one side is not actually been bled yet or something I would hate to think that the little pump up front can determine to not shoot brake fluids through one line of the rear brakes I wouldn't think that would be a thing It should pressurize both lines going to the back which is your two drums or your two wheel cylinders to be honest about it now I have seen people do the rear brakes and not have the drum ears in the slots correctly on the wheel cylinder and when the brakes try to engage the wheel cylinder pistons will be almost to their limit of travel pushing out on the rubber boots of the wheel cylinder and making fluid drip that takes a while for you to see coming between the drum and the backing plate so if you did the rear shoes while all this other stuff is going on You could have that problem I may have a picture of that going on somewhere I'll have to look It is very difficult to see and some mechanics will take a long time to pull that drum off and have a look they'll do everything else but they know they have that right then they pull the drum off and they see exactly what I'm talking about I've seen this twice on only generation 2 because the others have rear discs.
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    My first impression is you have an air bubble problem and that portion of the brake system was isolated when the control system sensed it as a leak. As previously mentioned, a good system bleed will likely fix that.
     
  5. Michelbanjolo

    Michelbanjolo New Member

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    The full bleed was a success. I was at least able to drive about 20 miles without it coming on, which is double than the record before, and generally it'd turn on within a mile. I feel rather silly not having just tried to do the entire thing right.

    The engine shuddering is still a thing. It would happen whenever I accelerate quickly, especially when crossing the 30mph threshold it seemed. It's almost certainly unrelated, so I'll look into it a bit more now that the ABS seems to be working. If anyone has any suggestions, let me know. I replaced the spark plugs a little over a year ago so they should be good. Perhaps the coils? If I can't figure it out, I'll probably make a different post with a title more relevant to the issue as it appears unrelated to the brakes.
     
    dolj and Brian1954 like this.
  6. dolj

    dolj Senior Member

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    Fake spark plugs are a real problem all over online sites like Amazon and eBay, so depending on where you bought your plugs, you might just pull one plug and inspect it. As well as coils, it could be injectors.
     
  7. Aloe

    Aloe Junior Member

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    If you buy from Amazon, be aware that there are many third party sellers on there and thus it could be a fake. HOWEVER if you buy from Amazon and it is SOLD BY AMAZON, then it should be fine.
     
  8. dolj

    dolj Senior Member

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    I'd to think that would be the case ...
     
  9. ChapmanF

    ChapmanF Senior Member

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    It's been noted that Amazon may ship you a product from one marketplace seller if you ordered from a different marketplace seller, Amazon thinks they are the 'same' product, and they have it from the one seller in a warehouse closer to you.

    The white paper that described that practice did not name the marketplace that was doing it, but it definitely has happened to me ordering from Amazon, so either they were the unnamed marketplace in question, or somebody else does it too.

    In my case, I noticed because the thing I received even showed up in the packaging of the seller I had deliberately chosen not to buy from.

    What I don't know for sure is whether they also play that warehouse-funging game with "sold by Amazon" merch, or not.