Parking brake light stays on, NOT the switch

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cacao, Dec 28, 2020.

  1. cacao

    cacao Junior Member

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    I have a 2006 Gen 2 Prius, and the parking brake light stays on when the parking brake is released. I have checked the switch at the back of the pedal assembly, and it has not moved. I removed the single wire connector from the switch, and the light stays on. I have shorted the connector to ground, and the light stays on, so I think that I have eliminated the switch as an issue. The brake fluid is not low, and there are no signs of fluid leek anywhere. Both of the rear brake lights work, so it is not that. The brakes themselves work fine, and are not spongy. Where do I look next?
     
  2. dolj

    dolj Senior Member

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    Have you scanned the car for brake codes yet? If not, do that as that light also doubles as a brake system warning light.
     
    #2 dolj, Dec 28, 2020
    Last edited: Dec 28, 2020
  3. rjparker

    rjparker Senior Member

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    The wire to the skid control ecu could be grounded. You could measure the dc voltage from that wire to chassis to verify. Disconnected it should not be zero or close to zero volts. 57C492D4-D0BC-4FCE-8000-DEC73409A98D.jpeg
     
    #3 rjparker, Dec 28, 2020
    Last edited: Dec 29, 2020
  4. JC91006

    JC91006 Senior Member

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    Maybe you should just go get a brake inspection, make sure your brakes are not low (especially the rears)
     
    edthefox5 likes this.
  5. cacao

    cacao Junior Member

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    I've scanned for codes, got none. I checked the front pads, they are good. I will check the rear shoes as soon as I can.
     
  6. cacao

    cacao Junior Member

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    The rear brake shoes are all between 3.38 - 3.83 mm thick, well within the specs. and everything else on the rear brakes look fine, clean, no leaks. I will check the parking brake switch voltage next...
     
  7. cacao

    cacao Junior Member

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    The voltage at the switch is 10.48v. So, any ideas of where to look next?
     
  8. cacao

    cacao Junior Member

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    OK, at this point the parking brake light is on (red), also the brake warning light (yellow) and the ABS light (yellow). Now I'm really confused.
     
  9. edthefox5

    edthefox5 Senior Member

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    Do you know what the brake boost noise is sounds like a rattle snake and and will go on briefly every time you step on the brake?

    You may have a failing ABS brake actuator and if so that pump will be on non stop. There's a poster right next to you the previous thread thats complaining about his brake light on too. His may be the switch on the E brake though.

    How many miles on your car?
     
  10. cacao

    cacao Junior Member

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    The car only has 77132 miles on it. The brake boost noise only runs for about a second when I turn on the car.
     
  11. edthefox5

    edthefox5 Senior Member

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    That's good ABS actuator is not leaking.

    Low miles on the car does not bode well for the hybrid battery though.

    The car is throwing many codes and whatever OBD device your using is not picking them up. What are you using to diagnose the codes?
     
  12. cacao

    cacao Junior Member

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    I'm using a bluetooth code reader sending to Torque on my phone.
    For what it's worth, I have also used the jumper wire on the OBD port method, and also not got codes. Also, using the jumper wire and pumping the brakes, I can get all of the lights out, but they come right back after restarting the car a couple of times.
     
  13. dolj

    dolj Senior Member

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    This tells me there ARE codes. Have you tried Dr Prius? Another member recommends that as it can also retrieve sub-codes from the freeze frame data.

    What do you see when you bridge TC and CG (pins 13 and 4)?

    Prius OBD2 port.jpg
     
    #13 dolj, Dec 29, 2020
    Last edited: Dec 29, 2020
  14. cacao

    cacao Junior Member

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    I've tried Dr Prius, and all I get are readings on the battery module. When I bridge TC and CG pins, I get a flashing ABS warning light, but it doesn't flash a code, it is just a consistent even non-stop flashing.
     
  15. cacao

    cacao Junior Member

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    Well, now I find that there are even more problems. The maint required light is on, and I drove the car a bit earlier this evening, and, as far as I can tell, the regenerative brakes are not working. Also, while all of the other screens on the multi-display are fine the energy monitor screen is blank. At this point, there are so many things going wrong, I wonder if I should start all over with a new thread?
     
  16. dolj

    dolj Senior Member

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    That is nothing to panic about, all it means is that 5000 miles have rolled around since the last time the light was reset. You are due an oil change.
    Do you have problems with the combination meter (CM) - that's the part of the dash display that shows your speed, fuel gauge, etc - going dark? The above symptom is consistent with that.
    Something is not adding up here. You should have all the warning lights flashing, the same as the ABS light if you have no codes in any system. What is your history with this car? Have you owned it for a long time or have you recently purchased it?

    If I was the suspicious type I might go looking to see if there is tape covering the other lights. Or even worse, someone has removed the LED lamps from the CM. Or an innocent explanation might be the CM is not functioning correctly.
     
  17. ChapmanF

    ChapmanF Senior Member

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    At times, people have jumpered Tc to CG and posted phone video of the dash lights. Can be worth a thousand words.
     
  18. cacao

    cacao Junior Member

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    Thanks for the info on the Maint Required light, I remembered that too last night, after I got finished panicking.
    The combination meter is fine now. It stopped working, and I replaced the little bad capacitor on the back of meter to make it work again.
    I have owned the car from new. This last year the car sat unused and the battery went dead. Some fool (ok, it was me), crossed the cables when jumping it to start up my trickle charger. It blew the main fuse bar, replaced it and a couple of small fuses, and replaced the battery. now that brings me up to where I am now.
     
  19. dolj

    dolj Senior Member

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    You may need to go over your work and check the CM is plugged in properly.

    In another thread by pEEf he said:
    It may not be a problem seeing as you did not swap from another car, but check the inclinometer is plugged in correctly. It is the plug that plugs in on the short side of the CM PCB.
     
  20. cacao

    cacao Junior Member

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    I am considering getting Techstream and a cable to try to read the codes. Would this be a good idea?
     
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