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P Lock C2310 Fix Fixed Solved Solution

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by strawbrad, Nov 18, 2019.

  1. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    They are dozens of threads on the dreaded P Lock problem. Few of them lead to a solution. This thread title is intended to stand out and lead others to a simple repair.. It seems there is more than one possible cause. My 2008 Prius had an intermittent P Lock problem. This You Tube video shows the source of the problem with my car.



    Here's a shot of the freeze frame data from the C2310 code. The eighth line of the left column labeled "Battery Voltage Value" showed .62 volts. That voltage is what the Transmission Control Computer is reading at pin 13. The computer needs a constant 12 volt supply to retain the memory of the P Lock mechanism position. P Lock 1.jpg

    The You Tube video shows the fault can lye between the 7.5 amp "P Con" fuse and this plug next to the positive jump point in the engine bay fuse box. It's the blue wire that leads from the P Con fuse to pin 13 on the Transmission Control Computer. On my car the pin for the blue wire had corroded to the point of breaking.


    P Lock 2.jpg

    I installed a jumper wire from the P Con fuse to the blue wire which restored a good 12 volt supply to the Transmission Control Computer.

    P Lock 3.jpg
     
  2. ChapmanF

    ChapmanF Senior Member

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    Another thing I like about this post is that it's a concrete counterexample to the idea that a code reporting a low voltage somewhere is necessarily a reflection on the 12 volt battery.
     
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  3. SyCo

    SyCo Member

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    My 2004 Prius with 244,000km (150,000 miles) started to show the red triangle with the parking message. I did connect my Techstream and saw the battery voltage at 0.5 V...I then looked at the white plug in the fuse box but all pins were like new. Using a voltmeter on pin 13 (blue wire) I was reading 0.52 V. Following your advice, I've installed a small wire from the 7.5A P Con Fuse and now everything is back to normal !! Thank You very much OP
     
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  4. Jharv321

    Jharv321 New Member

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    Thanks for the info. I just had to do this to my 07. I’m just curious if there is a way to trace the issue to fix it under the fuse box.
     
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  5. jack23

    jack23 Junior Member

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    I got the P Lock message and red triangle on my 2004 recently. Added a jumper from P CON MAIN fuse to blue wire in connector and problem was resolved. Thanks for that!

    But the ends of the jumper were just pushed into fuse connector and the back of the connector with the blue wire, and I wanted to do something more reliable. When I pulled the jumper out of the connector blue wire pin, half the blue wire terminal came out with it! So I added an inline fuse between the 12V main input in the fuse box to the now-loose end of the blue wire. I moved the 7.5A fuse from P CON MAIN to the new inline holder so the original fuse slot was empty. All good, except, the car would not power up! Paniced a bit, then put another 7.5A fuse in that empty P CON MAIN slot, and now everything powers up and works again.

    I had checked the wiring diagrams and it seemed like the P CON MAIN fuse only feeds that bue wire terminal on the connector, but that must not be true if I still need both that fuse AND the new inline fuse. Is there another connection to something else in the fuse box that is powered from the P CON fuse? SHown in the wiring diagram?

    And, secondary question - should I consider using 5A or lower fuses now that it seems like the load must now be split between the original fuse and the new inline fuse?

    No idea if we could trace the runs under the fuse box, but I suspect the problem is mostly/usually the connector with the blue wire, and I wonder if that terminal pin could be replaced and resolve this issue in some cases.

    Thanks,
    John
     
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  6. Figster10

    Figster10 Member

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    This worked for me with a Transmission ecu issue code. It was intermittent and with the same symptoms everything went away like I never had the problem before. My only question is why does this happen? Is there a short somewhere or a loose wire? I know some folks have suggested replacing the wire with a part number but this seems to be enough here.
    Thanks again
     
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  7. Ben Pidder

    Ben Pidder New Member

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    This worked for me as well, many thanks!!
    It solved the following issues described at
    Red triangle of death won't disappear after new 12V battery | PriusChat

    Finally been able to bring the car to the Toyota workshop, they found the following current codes:
    • C2310: Transmission control -> 'open or short circuit in battery circuit'
    • C1241: ABS/VSC/TRC -> 'low battery positive voltage or abnormally high battery positive voltage'
    • C1256: ABS/VSC/TRC -> 'ACCumulator low pressure'
    and a historic code that might be relevant:
    • B2796: Immobiliser -> 'No communication in immobiliser system'.
    • B2799 is found by dr Prius-app -> 'miscommunication between the Engine Immobilizer and the Hybrid Vehicle Control ECU'.
    Apart from the red triangle and warning described above, some strange issues occur regularly these days:
    1. after shutting down the car and retrieving the key from the system, the car starts up again without the key in the sockety. It is in the ig-off mode then. This only happens once, after pushing down the start/shut button another time it does not happen again.
    2. sometimes when the car is not on, all electricity drops, the car does not respond to the key or gives an indication the door is open or anything else. The 12V battery still measures 12.5V, but there is no current in the fusebox. Electricity restores after a couple of minutes without anything happening
    3. electricity does not drop during driving, however, each trip, at least once a warning beep sounds without any indicator light on the dashboard coming on.