Hi need help and support after electrical short

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Victorio Mo, May 23, 2026 at 1:35 AM.

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  1. Victorio Mo

    Victorio Mo Member

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    Hi Dear all,

    After cleaning HV fan I installed it back and tested it , everything was normal. Then tried to reconnect custom alarm and accidently make very short electrical short. My bad.

    After this everything went crazy.
    Radiator Fan starting instantly (on cold car). Panel displays some weird staff, see pic. All gear letters lit around letters and start flashing.
    Looks like fuse stayed alive and something else happened, will try to pull radiator fan fuse and read codes . For now disconnected 12V battery.
    By the way is radiator fan on fuse or relay, tried to find it and could not to disconnect

    Appreciate if you have advice .
    upload_2026-5-22_22-31-24.png

    If I'm right main radiator fan is on the same fuse with ECU
    upload_2026-5-22_23-7-15.png

    And the code is U0293 Lost Comm with ....
     
    #1 Victorio Mo, May 23, 2026 at 1:35 AM
    Last edited: May 23, 2026 at 2:46 AM
  2. Victorio Mo

    Victorio Mo Member

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  3. PriusCamper

    PriusCamper Senior Member

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    Was it reverse polarity? If so check/replace fuseable link.... But first step is having strong healthy 12v power as most of your symptoms could potentially be resolved by that alone.
     
  4. Victorio Mo

    Victorio Mo Member

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    Thanks PC! Not sure about reverse polarity, just simple + into the body(-).
     
  5. PriusCamper

    PriusCamper Senior Member

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    The square boxes in place of the gear shift position is usually an indicator of system being below 12volts in power. Check all your battery connections and health of 12v.
     
  6. Victorio Mo

    Victorio Mo Member

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    Thanks ! 12V is in good shape, but I will prepare.
     
  7. ChapmanF

    ChapmanF Senior Member

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    They could also indicate that the combination meter isn't able to communicate with the HV control ECU (U0293 ⇒ Lost Communication With Hybrid Powertrain Control Module) so it can't find out what gear shift position to show you.

    Communication U codes are a little special in that you want to know which ECUs can't talk to each other. The code is one ECU (say X) saying it can't talk to some other ECU (say Y), and the code itself tells you which ECU is Y, but not which ECU is X.

    That's where it helps to have a scan tool that doesn't just show you codes, but groups them according to which ECU reported them. Then you have both X and Y and you know you've got to solve a communication problem between those two ECUs.

    (It can also be more than two: several ECUs in the car want to communicate with the HV control ECU, so if more than one of them can't, you could have more than one U0293 code. On the nice kind of scan tool, you would see each U0293 code listed under the ECU that reported it.)
     
    #7 ChapmanF, May 23, 2026 at 9:34 AM
    Last edited: May 23, 2026 at 9:41 AM
  8. Victorio Mo

    Victorio Mo Member

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    Hi ChapmanF!!! So glad to see you here !!!!!
    I will try to get TechStream connected, Will try it on Mon.

    I learned that we can not just de-fuse radiator because it's on MUSB without removable fuses. They made it for protection.


    Thanks to all.
     
    #8 Victorio Mo, May 23, 2026 at 11:27 AM
    Last edited: May 23, 2026 at 11:52 AM