1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Strange electric issue - post rear view mirror destruction... related?

Discussion in 'Gen 2 Prius Main Forum' started by PriusPaddler, Aug 18, 2021.

  1. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    Yesterday a large angry child ripped my rear view mirror off my 2009 Prius (230,000+ miles) and pulled so hard, the wires separated and the glass broke, rather than the glue. Got child under control, and drove the car (by myself) for 100+ miles, no issues with driving. Today, drove another 30 miles, no issues...

    Then after lunch today, I went to take a different child to an event, and one mile from home it seemed the car quit. This curious child had been playing with the wires hanging from the ceiling (not sure that's related, but just in case). There are three wires hanging that used to be connected to the mirror somewhere. Wires were not destroyed, but may have touched each other.

    My rear view mirror is the kind with 3 garage door buttons and on and off buttons. I never use any of those buttons.

    When the car stalled out one mile from home, I turned it off and then on again. I was able to drive forward, but here's how that looked:

    - no power steering
    - no air conditioning
    - no speedometer light showing
    - dash lights literally flashing: all gear lights (could not tell I was in drive) and gas gauge bars (could not tell the tank was full)
    - dash lights on solid: seat belt light, TPMS light, ABS light,brake light
    - Info display had a few small things lit up maybe but not the usual photo of engine use or mpg

    There was NO check engine light, no red triangle light at all

    - fan worked to blow the 90 degree air around
    - windows worked
    - brakes worked, not sure if they were "normal" or not
    - hazards worked
    - door locks worked

    I limped my way to the dealer, where they are initially stumped. They are finding a Prius "expert" to examine and warned me it could take days (ahem "thousands" probably) to figure it out.

    I did NOT think to plug in my own ODB2 reader. :( busy getting kiddo home in an uber and canceling his appointment.

    Any ideas?

    I do not THINK it's related but 10 days ago, the car was diagnosed with a throttle body actuator(?) problem that occurs intermittently. I deferred repair as it can go weeks between issues. Those symptoms are totally different than above, but this is the only known problem with the car so I mention it "just in case".
     
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    A quick glance in the wiring diagram (more info) for the circuit that powers that mirror would probably show you directly which fuse blew when child #2 boinked those wires together.

    Alternatively, just testing all the fuses like an animal would probably get you the same place, just with more work and less diagram-glancing.
     
    PriusPaddler likes this.
  3. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    Funny, I asked the dealer intake person if it could have blown a fuse, and he was not inclined to think so. Made a big deal out of explaining to me that a blown fuse means the power can't pass through it (duh). I shoudn't have panicked and headed to dealer - should have known to come here first!! (Although checking each fuse on a 90+ degree day is not my idea of a good time.) Thank you.
     
  4. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    You have hit on one of the big reasons I prefer wiring-diagram glancing, indoors, in a comfy chair.
     
    PriusPaddler likes this.
  5. dbstoo

    dbstoo Senior Member

    Joined:
    Oct 7, 2012
    1,365
    730
    0
    Location:
    Near Silicon Valley
    Vehicle:
    2024 Prius Prime
    Model:
    XSE Premium
    The first thing that occurred to me was that your kid managed to short out the CAN bus and in doing so it might have screwed up one of the chips that help pass the data from one device to another. That would account for your symptoms.

    The second thing that sprang to mind was that you need to teach your kids not to touch wires. Any wires. At any time. They can be dangerous. They can be deadly. They can cause damage. It's not enough to say "the car's 12 volts, and that's safe". Kid's don't have a way to tell when it's safe and when it's 240V.
     
    PriusPaddler likes this.
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I don't think there are any CAN bus wires near the mirror on a 2009.

    A later generation with a LKA camera up there, maybe. But not an '09.
     
    PriusPaddler likes this.
  7. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,404
    6,061
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    The anti-glare garage door opener mirror has three wires. One goes to ground at the left side cowl panel, one is supplied by the 15 amp DOME fuse and one is supplied by the 7.5 amp ECU-IG fuse, which receives power from the IG1 relay.

    The DOME fuse is in the underhood fuse box and the ECU-IG fuse is in the people compartment fuse box near the drivers left knee.

    And yes, fuses can open following an over current situation, but still allow marginal contact of the element ends resulting in intermittent weak power.

    my experience has been that flashing dash lights (like gear indication) are often caused by very low 12v being supplied to the circuit.......

    personally, I would just tape up the exposed wires, replace both fuses and see what happens.

    I would like to think that ANY tech that was informed of a transient like two wires touching would be bright enough to at least check the simple things first....but fools are everywhere...
     
    #7 TMR-JWAP, Aug 18, 2021
    Last edited: Aug 18, 2021
    PriusPaddler likes this.
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Might not even be that exotic. Could have flat out blown one affected fuse, without disabling everything in the car as that tech seemed to think ... seems like maybe an underestimate of the number of different circuits there are in the car.
     
    PriusPaddler likes this.
  9. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    ECU-IG fuse fixed it!!!

    Most expensive fuse ever, but thanks to you guys, at least three people learned a lesson from this, including me!

    Thank you thank you thank you!
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,404
    6,061
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Always good to hear another success story!!!

    Glad the car is back in action!

    And if this person:

    dealer intake person

    needs lessons, have him give me a call.......:)
     
    PriusPaddler likes this.
  11. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    For the record, the dealer recorded that my car showed 13 different dtcs:

    p0A0F, 3108, u0129, 0146, P2103, U0129 (again? Or the dealer made a typo), C1242, 1310, B1421, 1412, 2286, 1650, and 1271.
     
  12. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    Will do.

    At least he wasn't too proud to pass along your recommendation to the tech working on the car. I'm sure they get a lot of people self-diagnosing or armchair quarterbacking with less merit. And they shaved off their diagnostic estimate $$ by more than half and don't seem to have charged me even a penny for the fuse, so it could have been worse I suppose.

    Maybe they used one of the fuses I had in my glove compartment, LOL.

    That'll teach me for panicking and thinking there was no way this was a DIY solution.
     
  13. PriusPaddler

    PriusPaddler Member

    Joined:
    Oct 19, 2017
    150
    29
    0
    Location:
    Twin Cities, MN
    Vehicle:
    2009 Prius
    Model:
    Base
    And I got to drive a brand new Camry for a day. Which just confirms that I don't want one, but I don't think I've ever driven a brand new car before so it was worth that.
     
  14. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Sure, again; that's common for Uxxxx codes, which are communication fault codes. U0129 means "hey, I'm not able to talk to the brake ECU", and if there are two or more ECUs in the car that are all finding themselves unable to talk to the brake ECU, they'll all say U0129.

    That's why the dealer really should not have just given a list of codes run together, but should have grouped them together by which ECU gave which codes. That's the way their Techstream software shows them, grouped by ECU. If this had been a trickier problem to diagnose, it might have been really useful to lay out the car's network diagram and know which ECUs weren't talking to which.
     
  15. BigCankles

    BigCankles New Member

    Joined:
    Oct 1, 2024
    1
    0
    0
    Location:
    Ohio
    Vehicle:
    2012 Prius
    Model:
    IV
    I joined and came to post here simply to say THANK YOU. This solution helped me a ton this AM.

    I had hardwired a radar detector and dashcam to my rearview mirror, and knew I had touched the wires during testing before buttoning everything up.(I know, I'm an idiot) Put insulation sleeves and buttoned everything up, but could not figure out what was causing the Hybrid system error, etc., as the DOME fuse was fine.

    Thank you thank you thank you.

     
  16. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,867
    16,188
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV