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Dash display won't turn off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Matt in AK, Sep 3, 2019.

  1. Matt in AK

    Matt in AK Junior Member

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    Our 2009 Prius won't completely turn off... One presses the power button to shut down and the dash display stays on, flickers and drains the battery. I have tried changing the Combo Meter, cleaning the power button and it still does it. One time, while it was flickering, I removed the power button and the flickering continued.
    I wonder if it would help to replace the power button ?
    It is slightly intermittent, occasionally but rarely working fine.
    Any thoughts ?
    Thanks, Matt in Craig, AK
     
    #1 Matt in AK, Sep 3, 2019
  2. bisco

    bisco cookie crumbler

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    how is the 12v health?

    are you sure the new combo meter is good?
     
    #2 bisco, Sep 3, 2019
  3. Matt in AK

    Matt in AK Junior Member

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    Well, it seems so, I bought a brand new combo meter, I guess it could be bad. The same problem was happening before and and after the combo meter change. I did not think it was likely that the new and old combo meter caused the same problem. I sent in my used combo meter and it seemed to have tested well on the bench.
    The dash lights that do not go off or flicker include the speedometer, gear position etc.. and the "no key" and "maint" yellow lights stay on or flicker.
    When driving and when in the ready mode all is well driving, but the "no key" yellow light stays on while driving.
     
    #3 Matt in AK, Sep 3, 2019
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  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I do not think the POWER button is causing the problem, since when you disconnected it there was no change to the flickering.

    I suggest that you look at the IG1 relay to see if it is stuck in the closed position. That relay is located in the driver's side relay box below the lower instrument panel finish panel.

    Hit the relay case with a screwdriver handle when the car is supposed to be IG-OFF to see if the relay will release. If that doesn't help, unplug the relay to see if that stops the flickering.

    If the IG1 relay is working correctly, maybe the power source control ECU is having a problem.
     
    #4 Patrick Wong, Sep 4, 2019
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  5. Matt in AK

    Matt in AK Junior Member

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    Ignorant here....
    What is the IG1 relay and what does it look like ?
    Power source control ECU ?
    Thanks Patrick
     
    #5 Matt in AK, Sep 4, 2019
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you can find the relay box, the inside of the lid might have a map that identifies the various relays and fuses.

    Or you can obtain the electrical wiring diagram for your model year at techinfo.toyota.com
     
    #6 Patrick Wong, Sep 4, 2019
    Raytheeagle likes this.
  7. Texas Hybrid Batteries

    Texas Hybrid Batteries Senior Member

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    I agree with Patrick that power is probably being supplied to the 10A GAUGE circuit when the car is turned off. You may also try removing the GAUGE fuse to see if that stops the flickering. If it doesn't that may indicate that the power is coming from somewhere else, like a damaged wire harness.

    upload_2019-9-4_16-49-31.png


    The GAUGE fuse and IG1 Relay are on the driver side J/B to the left of the steering column. To access the relay you have to remove the driver side lower trim panel and a small access cover in front of the J/B (3 10mm nuts). The power source control ECU is under the dash pad directly in front of the steering wheel.
    upload_2019-9-4_16-39-38.png

    upload_2019-9-4_16-56-46.png

    When you're looking at the front of the junction block the IG1 relay is in the bottom left corner.

    upload_2019-9-4_17-2-19.png

    Here's a link to Hobbit's Body control ECU teardown tutorial. http://techno-fandom.org/~hobbit/cars/bodyecu/
     

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    #7 Texas Hybrid Batteries, Sep 4, 2019
    SFO, Skibob, Raytheeagle and 1 other person like this.
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