Hang on to your pants! We've got a "p" Lock triangle of death mystery.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Maxx, Jul 8, 2020.

  1. Maxx

    Maxx New Member

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    Here we go, a mystery on our hands. I have searched this sucker.
    I start my car and get the "p" lock message and triangle. It allows me to drive it, I drive it 2 miles and stop. Full shutdown. Go to restart, it starts, and goes into ready but will not shift. It beeps the beeps of attempted shifting.

    Dash symptoms:
    Red triangle
    "p" lock warning
    (!)
    VSC

    Techstream symptoms:
    Round 1 (before clear)
    p3102
    c1300
    c1310
    c1377
    u0123
    u0124
    u0126
    b1421
    b1443
    c2304

    Round 2 (after clear, codes immediate)
    p3102
    c1310
    b1421
    c2304

    Attempted fixes:
    New 12v Battery
    Jump started in addition to 12v battery
    Pulled and waited on 7.5a fuse
    Pulled neg cable for 2min
    Jump wired 7.5a fuse to Blue #4 wire in harness
    Checked all fuses under hood
    Stepping on and off of parking brake a lot
    Power on off a lot
    Code reset w/ techstream.

    Red herring:
    When I attempt to restart the car, the door dinger and everything is functioning, attempt to start it, no success.THEN door dinger is gone, radio stops working, clock dies, no dome lights. I check the fuse box, the fuse is GONE, not there, missing. I put a spare into its place and all the above electrical start working again.

    Red herring #2:
    Previous owner claims to have replaced brake unit under hood. Clearly did a subpar job. Likely car has more history than told.

    Help please.
     
  2. Maxx

    Maxx New Member

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    Next thoughts.
    Check/Replace Parking Control System Relay
    Remove and reinstall parking actuator harness.
    Replace all fuses that could be linked.
     
  3. Maxx

    Maxx New Member

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    Let's add another clue.
    The fuel gauge has 1 blinking bar on it. (no other bars present, it has more fuel than that)

    Finally got the car towed to the house. My next step is going to be to check the connection on the trans ecu, any help on getting to this easily?
     
  4. edthefox5

    edthefox5 Senior Member

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    P3102

    Transmission control ecu sees malfunction

    Standard mileage mystery in post

    Wire harness
    Trans ecu failure
    Hv control ecu
    Power source ecu

    And lots of brake issue codes.

    It’s a winner.

    Ok let’s pull some teeth where did the car come from is it a rebuilt title and for the love of god how many miles on it.
     
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  5. Maxx

    Maxx New Member

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    Now we're cooking!
    Mileage, 175k.
    Car seems to have lived its life on Hawaii, no corrosion anywhere obvious

    Clean title, Aftermarket HV pack... BUT I bought it with a mis-colored, a bumper that had been removed and the lower grills messed up, and unsecured shrouding over the radiator, from an owner who was not above falsifying information.

    I have gotten the "p" lock before, but pulling the 7.5 fixed it. Seemed like a bad battery was the culprit from leaving the door open.

    Current thoughts, however the haz was receiving power w/o a fuse has stopped working. ( a fuse in the haz position was needed to get it to beep and recover the interior electronics. I had to use the "horn" fuse to put into its space, the "horn" is now open. -Does anyone know of anyway to gerry the "haz" circuit in an inconspicuous way w/o a fuse?
     
  6. Maxx

    Maxx New Member

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    I either found an answer tonight or a rabbit hole that goes to the wrong place. Dissassembly of the dash to get the the trans ecu presented a pair of 12ga speaker wires running from the drivers side, spliced into the engine ecu harness.

    Jiggling and manipulating these wires made the fuel gauge stop blinking and read correctly. Also allowed the buzzer and etc to function without a fuse in the haz spot.

    The fat blue wire running next to the harness (stock looking wire) is spliced into.
     

    Attached Files:

  7. edthefox5

    edthefox5 Senior Member

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    Oh Lordy what the hell is that?

    Only popular mods for a g2 were installing an ev switch so you could maneuver around a parking lot with the engine off and the other was an automatic door lock when you put the car in gear it locked all the doors but using that size wire is idiocy.

    I think you chopped into the trans ecu harness for the auto door lock mod. There is more knowledgeable guys on here with that mod That will come around soon but don’t know why else you would chop into harness otherwise with speaker wire no less.

    You must restore that butch job. If you can trace the Chopped wires to the plug and take a picture of that plug I can tell you that wires function.

    Restore the wires function.

    But may be a moot point you may have a bad brake actuator and that’s an expensive repair so take a step back assess your skills your time and how much time and money you want to sink iinto this ghost ship.

    Be glad to help with the wiring issue though.
     
  8. Maxx

    Maxx New Member

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    Here's a new splash of information.
    The previous owner bought the car from the dealer. It was a dealer car from 07-10. Previous owner claims they did not do any modifications, only replacing the HV and brake module. Monday I will be reaching out to the dealer to see if they have records of this speaker wire modification. Fingers crossed that the stars align and they have record of what and why that was done. It seems like a fair guess that whatever is being bypassed/changed is allowing the interior to function without the HAZ fuse.

    The splice job splices into a green/aqua wire at either the Hybrid Vehicle Control ECU or the Engine Control Module, then heads into the driver side section up near the Power Source Control ECU or the Daytime Running Light Relay.

    -What is steering you towards a brake control issue, I'm not seeing that in the fault codes. I understand though that the whole system is interlinked.

    -Is it a fools errand to chase down this wiring job, I'm nervous/ suspicious that it may be a problem, but not THE problem.
     
  9. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    DTC P3102 has seven (7) related INFs (subcodes), knowing the associated INF may save time and money when troubleshooting.

    Since you're using techstream as an OBD2 scanner, are you able to retrieve the INF(s) for the above DTC?
     
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  10. Maxx

    Maxx New Member

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    I will try and get that this evening!
    Off to the dealer to see if they have the service records.
     
  11. SFO

    SFO Senior Member

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    You can also run the VIN at : Welcome to Toyota Owners
     
  12. Maxx

    Maxx New Member

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    Evening update time:
    -Toyota dealer claimed it was illegal for them to tell me my car's service history.
    -The toyota website mentioned by SFO indicates there's more to the cars story, starting in PD not Hawaii, but there's not any information on there beyond 1 oil change @8,000 miles.

    Now for the fun:
    -Digging through the dash I traced the speaker wire all the way through, It is connected back to itself and seemingly only bridging a 20ga black wire from the ecu.
    -I found an aqua wire spliced into the harness from the steering control loom, it seemed to run into a wire sheath and into the certification ecu. BUT, further investigation revealed it was just sitting in the loom unconnected and appearing to never having been connected to anything (It is part of a 2 into 3 connection, where the 2 are still present and same colored).
    -There's a green and a blue wire spliced together, these appear to be from a brake pedal sensor. These wires also appear to be simply bridging a black wire from this sensor.
    -An identical blue wire (size and color) is present that does not go anywhere, just open.

    I went through TechStream, but I'm unclear how to find INF'. Here's some screen shots from tonight. 20200713_171725_compress44.jpg 20200713_171826_compress68.jpg 20200713_171850_compress25.jpg 20200713_172259_compress84.jpg 20200713_172331_compress42.jpg 20200713_172425_compress89.jpg 20200713_172907_compress34.jpg 20200713_172910_compress75.jpg 20200713_173003_compress26.jpg 20200713_174859_compress36.jpg 20200713_180925_compress92.jpg 20200713_180525_compress8.jpg 20200713_180659_compress77.jpg 20200713_180837_compress65.jpg 20200713_180837_compress65_1.jpg
     
  13. Maxx

    Maxx New Member

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    Additionally attempted to remove the parking actuator wire from unit, couldn't get my hands in there well enough.

    Current thoughts:
    Wiring may have been from an interlock or blow and go of sorts? Could be using the brake pedal as a break for the starting system.
    Trans ecu may be bad.
    A break in the wires somewhere.

    Still pondering:
    The car still does not need a fuse in the HAZ spot for the buzzer to function.

    Whats the next step in this diagnostic?

    I don't see any trans ecu diagnostic procedures.
    I don't know how to get the park actuator harness off, but it seem clean and tight.
     
  14. Raytheeagle

    Raytheeagle Senior Member

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    An example of the INF codes is the screen shot for P3102;).

    See detail code 2 and 3:).

    Those will help you narrow down the next steps(y).
     
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  15. edthefox5

    edthefox5 Senior Member

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    The short in the U phase is referring to one phase of the ac 3 phase power used to power the ac motors in the trans. One motor winding is shorted to ground most likely. Or...one leg of the inverter 3 phase ac output to the trans is shorted. Is the under carriage on this mutt all busted up?

    If not most likely the trans is blown has a shorted winding pretty common for G2's that have had the ever lovin' snot driven out of them.

    The car will never ever start with that short. Blown trans. Drop the trans fluid give it a sniff it will smell burnt. Starting to look more and more like a paper weight.

    3 phases of Delta AC voltage: U-V-W.
     
  16. SFO

    SFO Senior Member

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    On the "Health Check Results" page, is a hidden column of blue flowers/clouds (INFs), right between "Monitor Status" and "DTC".
     
  17. Maxx

    Maxx New Member

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    I'll plug the computer back into the car this evening.

    *The car starts, idles and does all the ICE things associated with it.
    The car is run fairly hard. The underbody is fairly clean, the rocker panels not so much.
     
  18. SFO

    SFO Senior Member

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    [​IMG]

    and

    [​IMG]
     
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  19. Maxx

    Maxx New Member

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  20. Maxx

    Maxx New Member

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    Here's tonights work on codes:
    3102-581
    -Harness
    -Trans ECU
    -HV ECU
    -Power ECU

    3102-598
    -Harness
    -Trans ECU
    -HV ECU
    -Power ECU

    2304
    -Shift control Assy
    -Trans ECU
    -Trans lock control
    -Harness

    2307
    -Trans ECU
    -Harness
    -Parking lock motor.

    From this, the only things that are present across the codes are a wiring harness/ connector problem and a Transmission ECU problem. Am I right in this thinking? or could they be triggering from different things?
     
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