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Prius won't start, flashes the combination meter for a split second

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Bigyums, Sep 10, 2022.

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  1. Bigyums

    Bigyums Junior Member

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    Hi Prius People! Please Help.

    I was driving home from work on the interstate about 65 mph, and all of the sudden there was a singular knock noise in the left front of the car. A small thud, and it was immediately followed by a caution - red triangle of death. At the time the MFD screen showed the HV battery at full charge, but quickly depleted as I pulled off the road. Engine stopped running as I was coasting to the stop. I turned the car off with power button, and tried to restart but it never would start again.

    Call the tow truck, we did try to jump, no issues with reverse polarity or anything like that. The jump didn't work, and nor did other 12v batteries.

    I checked the 100 amp fuse-link and it seemed fine. Checked most of the other fuses and nothing seems to be burned either, and the HV battery plug is in an has no issues either.
    Out of desperation I decided to change the 12v battery with a brand new battery that matched OEM. It didn't work.

    One other note. The HV battery was replaced this summer, with an Green-tec battery, but has not had any signs of trouble yet.

    Take a look at the video below where I try to start it, while holding the brake. The combination screen just flashes up for a split second and then seem to short out. Then the car does nothing.



    Battery powers up accessory mode just fine though. See video below.



    Does anyone know what I should check next. Thank you for your help in advance!
     
    #1 Bigyums, Sep 10, 2022
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    First thought is to see if the AM2 fuse in the underhood fusebox is blown. A common scenario is for the inverter coolant pump to fail and short - popping the fuse. That fuse also supplies power for the power source control ecu for most all "ignition on" circuits. Such as the combination meter (speedo) and ECM.

    If that fuse is blown, you can unplug the coolant pump and replace the fuse. There's a single wire (white with black stripe) connector near the left front strut tower underhood. That will disable the pump.

    The car should then run but keep the drive slow and not too long (no A/C) - otherwise the inverter will overheat and turn off. Then you would need to replace the pump- I only use a Toyota part as aftermarket parts have questionable reliability.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Sep 11, 2022
  3. bisco

    bisco cookie crumbler

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    put it on a lift to see if you hit something
     
    #3 bisco, Sep 11, 2022
  4. Bigyums

    Bigyums Junior Member

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    Thank you for the input! I doubled checked the AM2 fuse just now. It’s still good, visibly good, and took it out and tested for continuity ok.

    Just for curiosity I unplugged coolant pump after putting the fuse back in to see if that any effect. It did not, it’s doing the same thing.

    Any other ideas?

     
    #4 Bigyums, Sep 11, 2022
  5. Bigyums

    Bigyums Junior Member

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    It was a clear road, and during the day. I’m certain I didn’t hit anything, but thanks for the idea.
     
    #5 Bigyums, Sep 11, 2022
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  6. mr_guy_mann

    mr_guy_mann Senior Member

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    I would scan all the ecu's on the car with a capable scantool and see which ones respond. That would give clues as to which systems are working.

    Posted via the PriusChat mobile app.
     
    #6 mr_guy_mann, Sep 12, 2022
  7. Bigyums

    Bigyums Junior Member

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    Can't read the codes. Scanner and Tech Stream both won't recognize it right now without the car turning on.
     
    #7 Bigyums, Sep 16, 2022
    Last edited by a moderator: Sep 16, 2022
  8. Bob!

    Bob! Junior Member

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    I have a similar (if not identical) problem. Any luck finding a solution?
     
    #8 Bob!, Dec 23, 2022
  9. Bob!

    Bob! Junior Member

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    My profile says I have a 2013 Prius v (I do), but I also have a 2002 Prius and this is the vehicle with the above problem. Not sure how to add a second vehicle to my profile...

    But would love to fix the '04 that is experiencing the same prop that the OP is inquiring about.
     
    #9 Bob!, Dec 23, 2022
  10. Bigyums

    Bigyums Junior Member

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    Yes! Mine is fixed. The issue turned out to be a fried ECU board, behind the glove box. I have no idea how it spontaneously blew, but the replacement ecu has been working fine for months now.
     
    #10 Bigyums, Dec 24, 2022
  11. dolj

    dolj Senior Member

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    ECU board? Or do you mean PCB?
     
    #11 dolj, Dec 24, 2022
  12. Bigyums

    Bigyums Junior Member

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    ECU 89661-47070
     
    #12 Bigyums, Dec 24, 2022
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  13. dolj

    dolj Senior Member

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    That is the engine management computer (ECM).

    Interesting that it should fail in the way you describe.

    It is a shame you could not pull codes as that would have been interesting to see what they were, though not surprising with a failed ECM.

    Glad you got it sorted and are on the road again with the 2004.
     
    #13 dolj, Dec 25, 2022
  14. Bob!

    Bob! Junior Member

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    Thanks for the update! I was kind of thinking it might be one of the car's brains. Haha.

    How did you conclude that this was the failing part? Was it visibly fried? I'm hoping to diagnose mine and repair. And did you swap it out yourself? Thanks again.
    -Bob
     
    #14 Bob!, Dec 30, 2022
  15. Bob!

    Bob! Junior Member

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    Well, that wasn’t the problem. Or wasn’t it?

    I bought a used ECU from eBay and put it in today. The car turns on for a split second and then back off, as described in the following linked post where I started a thread about my non-start prob: 2004 Prius won’t start up. Died while driving. Warning lights blink then shut off. | PriusChat

    After reading this thread, I thought my ECU might be bad. Now that I've swapped it, either my ECU wasn’t the problem (and I, once again have no idea what the problem is) or the used ECU I bought is broken in the same way as mine.

    It might seem unlikely that the used eBay ECU failed in the same way as the original but I did once buy a used ABS actuator for a Gen 1 Prius and put it in (huge pain in the rear) only to learn that it did not work at all and wouldn’t even power up. So, it happens… ugh.

    If anyone has any ideas or suggestions, I’d appreciate it.

    Thanks.
     
    #15 Bob!, Jan 3, 2023
    Last edited: Jan 3, 2023
  16. Bob!

    Bob! Junior Member

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    UPDATE:

    I re-checked the AM2 fuse and it’s blown. Swapped the fuse and unplugged the inverter coolant pump and it started right up. Plugged the inverter coolant pump back in and started it up. Started smelling burny and smoke wafted up from the inverter coolant pump. Turned it off and ordered a new inverter coolant pump. Sounds like this was the problem all along. Ill update when I get the new inverter coolant pump in there.
     
    #16 Bob!, Jan 6, 2023
  17. cgalpin

    cgalpin Junior Member

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    Did this require any re-programming, and if so how did you do that?

    I am facing the same problem on a 2005 - can't start or go to ign-on, so can't get any obd2 reader (including techstream) to communicate with the ECU. All fuses including AM2 are fine, 12v battery good, have disconnected the white + white/black wired connector to the coolant pump near the fuse box. Headlights, radio, brake lights work.

    I am considering buying a used ECU to see if thats the problem, but want to make sure it doesn't need programming or there is a way to do this.
     
    #17 cgalpin, Jul 19, 2023
    Last edited: Jul 19, 2023
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