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Can I safely preform an ECU reset?

Discussion in 'Gen 2 Prius Technical Discussion' started by Karah, Aug 8, 2014.

  1. Karah

    Karah Junior Member

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    I want to reset the ECU & I was going to use these instructions http://www.ehow.com/how_6304073_reset-after-changing-o2-sensor.html
    I don't want to fry my system though.

    The reason I want to reset is I am using a fuel catalyst that is improving my engine, mpg, & emissions, but my results aren't going as I expected & I have been suggested to reset the system this way.

    Please advise!
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Just disconnect the 12V battery for a few minutes, then reconnect it. It is easiest to disconnect the negative cable where it bolts to the body.
     
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  3. Karah

    Karah Junior Member

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    Thanks for your response Patrick,
    I was advised by the previous owners not to disconnect the battery e.g. like if I had a dead battery & would need a jump start in a regular car.
    I would like to reset the ECU by pulling the fuse out simply. I just want to make sure it is safe for the Prius.
     
  4. bisco

    bisco cookie crumbler

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    i would like more power, mpg's and lower emissions... i'm sure your disappointing results are due to the lack of edu reset. all the best!(y)
     
  5. bisco

    bisco cookie crumbler

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    just pull the fuse, it's the same as if the fuse blew and you were replacing it. same with the battery, how would you put in a new one without disconnecting the old one?
     
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  6. edthefox5

    edthefox5 Senior Member

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    What product are you using?
     
  7. Fifine

    Fifine Member

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    It's Friday, and my brain is much denser... (no edu on earth can help me now!)

    So jokes and sarcasm aside, is there a fuse 1 can pull out to reset the ECU?
    Any other option besides unplugging the neg. battery cable?

    I'm just not gifted with tools in tight spaces.
     
  8. JC91006

    JC91006 Senior Member

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    Unless there is an issue with your car, there is no reason to reset it
     
  9. bisco

    bisco cookie crumbler

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    fifine? what happen to karah?:confused:
     
  10. Fifine

    Fifine Member

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    Don't know....

    I was "piggy-backing" on her question since I am also curious if there's another option to reset besides the battery cable removal.
     
  11. bisco

    bisco cookie crumbler

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    apparently not. but maybe check the owners manual for fuse descriptions. perhaps there is one for the 12 volt power. or there maybe one on top of the battery itself.
     
  12. Fifine

    Fifine Member

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    Manual doesn't list any fuse associated w/ ECU. Could be reader error in not finding.

    On regular cars, I would pull the EFI fuse. Is that applicable here?

    Just curious. Car is running fine. Psychologically, a reset sounds attractive, especially since it's a "new" car for me. :cautious:
     
  13. bisco

    bisco cookie crumbler

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    you seem well educated for someone who can't find their way to the battery negative connection with a 10mm wrench.:cool:
     
  14. Fifine

    Fifine Member

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    HAHAH

    Reading is easy. Torquing or twerking, even if it's only 12v is muy dangerous for me!!!
     
  15. bisco

    bisco cookie crumbler

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    maybe if you ask your mechanic real nice, he'll give you a freebie.;)
     
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  16. dolj

    dolj Senior Member

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    You can more easily disconnect the 12V battery at the positive terminal by unplugging the white plug. No tools required, and I do believe you could easily do it. :) If you can pull a fuse, you can do this.
     
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  17. bisco

    bisco cookie crumbler

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    that's a great idea! she might need a picture of the white plug and description.
     
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  18. Fifine

    Fifine Member

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    Thanks for looking out for me Bisco!

    Not familiar w/ the white plug. Thank you for the suggestion Dolj.
    I'll have a peek the next opportunity. Trunk is now filled w/ various cases of beverage - all non alcoholic :oops:


     
  19. dolj

    dolj Senior Member

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    When you get to it, have a look, I think you will see it quite clearly, but if you need a pic or two, just holla.
     
  20. Fifine

    Fifine Member

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    All right, finally had the time and empty trunk to try this out.
    (and my Macgyver friend for backup and tools....)

    As both dolj and bisco mentioned, there are white plugs that can be pulled out - which will be a quicker way (at least for mechanical wimps like me) to reset the ECU. They mentioned 1 plug, I pulled both....
    Be careful with the plug on the right; it is unusually long so take care pulling it out all the way.
    2 wh plugs.jpg

    I also noticed two fuses: one 5 amp, and one 50(?). I didn't pull those but maybe they will serve the same purpose as shutting down the battery?
    plug C U.jpg

    Finally, as mentioned many times before, one would need to re-program a few things lost due to the disconnect, e.g. clock, radio stations, etc.
    Remember:
    DO NOT CLOSE THE HATCH if the plugs are still disconnected - it was no fun crawling from the backseat to reattach. :oops:
    It was 92F outside.

    Take care putting the long white plug (on the left in this pic.) all the way back in. It will click.
    plugs out.jpg
     
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