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U0293 Lost Comm w/ Hybrid Powertrain Control Module

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by tracy ing, Feb 17, 2018.

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  1. tracy ing

    tracy ing Active Member

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    Vehicle:
    2005 Prius
    Model:
    N/A
    Mid December car threw P0A1D red triangle and would no longer go into gear. That code indicates no bus signal on the Hybrid Vehicle Powertrain Controller

    Replaced the Hybrid Vehicle Powertrain Controller to the right of the engine ECU behind glove box, code went away, triangle went away, but no shifting. Then jumped wires in the OBD with a paperclip and let car sit ON for 40 minutes to allow the new controller to sync, car then worked for 6 weeks thousands of miles.

    One morning car threw U0293 (his code means that the Hybrid Powertrain Control Module (HPCM) and other control modules on the vehicle are not communicating with each other) and all gear indicators are flashing, wont go ready or into gear. No triangle and engine fan is on. If placed in IGN, about 4 seconds later gears start flashing.

    I use a harbor freight code reader, I used to have to select one fo three modules in order to read codes, I no longer am provided that choice it jumps right to READ CODES as if only one of three modules are available.

    Started using a pdf file to trace and test wires, low confidence in pdf. On the powertrain module i think i see good ground test on two wires and no 12 volts on the two wires i think I was to test for 12 volts.

    All fuses under hood and in car fuse area were pulled and tested.

    I have the old controller and yet another one from ebay, three total, none of them change the current symptoms.

    New 12 volt battery installed.

    I suspect no 12 volts to controller, need help in confirming the correct plugs pins and WIRE COLORS to test for 12 volts on the Hybrid Vehicle Powertrain Controller to the right of the engine ECU behind glove box.

    In addition to that, where does the 12 volts for that controller come from, is it possible that even though the ODB is working that a relay or other ecu that must be fired up by boot up is not working and therefore no 12 volts is making it to the powertrain controller ?
     
    #1 tracy ing, Feb 17, 2018
    Last edited: Feb 17, 2018
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Check the following fuses: 20A HEV, 15A AM2. When you pull the fuses, see if you can measure 12V on one side of the fuse socket, to body ground.
    2. Check the IGCT and IG2 relays. Remove the relay, use an ohmmeter to determine the relay coil terminals and apply 12VDC to those terminals. Measure resistance across the switched terminals and make sure it is less than 0.5 ohm after accounting for resistance in the DMM test leads. If greater, replace the relay.
    3. If that doesn't help, get the electrical wiring diagram for your model year at techinfo.toyota.com so that you can determine the pin locations at the wiring harness connectors, wire colors etc.
     
    #2 Patrick Wong, Feb 17, 2018
    Last edited: Feb 17, 2018
    SFO, JC91006 and strawbrad like this.
  3. tracy ing

    tracy ing Active Member

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    OK I'll check all that, by the way 2005 prius
     
    #3 tracy ing, Feb 17, 2018
  4. tracy ing

    tracy ing Active Member

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    SON OF A B&*CH

    it was the HEV fuse

    GOOD CALL AND THANKS
     
    #4 tracy ing, Feb 17, 2018
    Fern1461 likes this.
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The next question is, why did that fuse blow?
     
    #5 Patrick Wong, Feb 17, 2018
    Raytheeagle likes this.
  6. tracy ing

    tracy ing Active Member

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    road salt and corrosion in the fuse box, fuse deteriorated fell apart
     
    #6 tracy ing, Feb 17, 2018
  7. ls40095

    ls40095 Junior Member

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    Are you familiar with the RX450H? I’m looking at one with the same DTC that took in some water. Won’t start ( ready light not lit) and that’s the only DTC that comes up
     
    #7 ls40095, Aug 7, 2019
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I am not, check techinfo.toyota.com for factory repair manual info.
     
    #8 Patrick Wong, Aug 7, 2019
  9. ls40095

    ls40095 Junior Member

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    The ECUPCU probably got fried
     

    Attached Files:

    #9 ls40095, Aug 7, 2019
  10. Skibob

    Skibob Senior Member

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    You must be good. People ask you questions about Lexus hybrids in a Prius website. :D
     
    #10 Skibob, Aug 7, 2019
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  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Not so good since I could not answer... :ROFLMAO:
     
    #11 Patrick Wong, Aug 7, 2019
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  12. ls40095

    ls40095 Junior Member

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    Patrick is unbelievable. I’ve even sent him money for answers!
     
    #12 ls40095, Aug 7, 2019
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  13. Raytheeagle

    Raytheeagle Senior Member

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    Have you checked the connections and fuses:whistle:?

    We’ve got an RX450h and it is a great ride:).

    I wouldn’t condemn the ECU until I checked all connections and fuses first;).

    Good luck and keep us posted (y).
     
    #13 Raytheeagle, Aug 7, 2019
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  14. ls40095

    ls40095 Junior Member

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    I’m considering buying it from an insurance company, so I can’t totally go over the car. Risk/reward
     
    #14 ls40095, Aug 8, 2019
    Raytheeagle likes this.
  15. Paulo219

    Paulo219 New Member

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    i have the same issue with my 2015 Prius. Could you show me what the 20A HEV fuse looks like or located, pls?
     
    #15 Paulo219, Jul 25, 2020
  16. Singh.seattle

    Singh.seattle Junior Member

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    Where is the igct and ig2 relays located in gen 3 prius?



     
    #16 Singh.seattle, Nov 18, 2020
  17. dolj

    dolj Senior Member

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    Maybe post your question in one of the Gen 3 forums.
     
    #17 dolj, Nov 19, 2020
  18. Singh.seattle

    Singh.seattle Junior Member

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    Ok g
     
    #18 Singh.seattle, Nov 19, 2020
  19. fa1984dy

    fa1984dy New Member

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    I have a 2011 Prius and the code saying no communication with hybrid power terrain module . Do U you recom
    Where is this fuse located?
     
    #19 fa1984dy, Oct 3, 2022
  20. dolj

    dolj Senior Member

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    Hi and welcome to PriusChat.

    FYI, your posts are moderated until you have 5 posts under your belt, so we don't see them until they are approved by a moderator. (Anti-bot spamming measure).

    You have posted in a Gen 2 forum although your 2011 is a Gen 3. Perhaps posting your question in one of the Gen 3 forums will get you better information.
     
    #20 dolj, Oct 4, 2022
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