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Red Triangle was intermittent, now constant

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dsturchio, Dec 30, 2015.

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  1. dsturchio

    dsturchio Junior Member

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    Location:
    NY
    Vehicle:
    2004 Prius
    Model:
    Two
    I swapped out the 12v Battery and the Brake Power Supply and the Control ECU Assembly no avail. I went through all of the steps in the service manual:
    1) Inspected the fuse (and I swapped it as well to be sure)

    2) Used techstream to check the value for "BATT VOL VAL" which I took to be Battery Voltage Value - this turned out to be 0. Another line read Battery Voltage Status at OFF
    -There was also a B+ Voltage Value which read 11.48, and another line B+ Voltage Status ON

    3) I checked the Harness and Connector for obvious issues, which I could find none. I sprayed electrical contact cleaner on each connector as well to see if that would help.

    I measured the resistance from pin 13 to the P Con Fuse and it measured below 1 ohm (which is good per the service manual).
    I then measured the resistance from pin 13 to a body ground and there was no reading. The voltage was also not reading.

    I assume this means there's a problem somewhere in the harness, connector, or individual wire. I'm not sure how involved it is to replace that or if its even worth it at this point.

    Thanks again for your input.
     
    #21 dsturchio, Jan 2, 2016
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    With the P CON MAIN fuse removed, measure voltage from the P CON MAIN fuse socket to ground. One of the terminals should measure 12V at all times even when the car is IG-OFF. If you cannot measure 12V at the socket, then you know the problem is within the fuse box.

    Assuming you get 12V at the P CON MAIN fuse socket, measure the resistance across the PCON fuse to confirm that the fuse is OK.

    After you've confirmed that there is 12V at the P CON MAIN fuse socket, and the fuse itself is good, then one possible remedy is for you to run a wire from pin 13 at the transmission control ECU wiring harness connector, to a 12V fuse protected source that is always on even when the car is IG-OFF. Then see if you log DTC C2310 or any other DTC.
     
    #22 Patrick Wong, Jan 2, 2016
    Last edited: Jan 2, 2016
  3. dsturchio

    dsturchio Junior Member

    Joined:
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    Location:
    NY
    Vehicle:
    2004 Prius
    Model:
    Two
    12V confirmed at P Con Main fuse. I'm working on that 12V fuse protected source. Thanks again.
     
    #23 dsturchio, Jan 3, 2016
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    One possible 12V source is via the 10A HAZ fuse which feeds the flasher relay, distributing power to the hazard lights. Pin 4 of the flasher relay receives 12V from the HAZ fuse at all times. That relay is located in the relay/fuse box under the instrument panel, driver's side.
     
    #24 Patrick Wong, Jan 3, 2016
  5. dsturchio

    dsturchio Junior Member

    Joined:
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    Location:
    NY
    Vehicle:
    2004 Prius
    Model:
    Two
    Is it possible to run an in-line fuse protected wire from the 12v battery?
     
    #25 dsturchio, Jan 3, 2016
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Location:
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    2015 Prius
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    Two
    Certainly. I suggested the flasher relay simply because it is already in the passenger compartment so the length of wire that you would have to run would only be 4 feet or less.
     
    #26 Patrick Wong, Jan 3, 2016
  7. waywalker

    waywalker Junior Member

    Joined:
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    Location:
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    Vehicle:
    2007 Prius
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    Huge thanks! :) I followed this exact route and the evil triangle is now gone. My first repair ever, too :)
     
    #27 waywalker, Sep 2, 2016
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