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

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

    Joined:
    Apr 5, 2014
    11
    2
    0
    Vehicle:
    2006 Prius
    Model:
    N/A
    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

    Joined:
    Mar 8, 2008
    18,200
    6,482
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    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.
     
    Bruce Berquist likes this.
  3. Karah

    Karah Junior Member

    Joined:
    Apr 5, 2014
    11
    2
    0
    Vehicle:
    2006 Prius
    Model:
    N/A
    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

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    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

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    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?
     
    Bruce Berquist and sfv41901 like this.
  6. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,817
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    What product are you using?
     
  7. Fifine

    Fifine Member

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A

    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

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    Unless there is an issue with your car, there is no reason to reset it
     
  9. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    fifine? what happen to karah?:confused:
     
  10. Fifine

    Fifine Member

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A
    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

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    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

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A
    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

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    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

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A
    HAHAH

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

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    maybe if you ask your mechanic real nice, he'll give you a freebie.;)
     
    Bruce Berquist likes this.
  16. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,855
    3,967
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    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.
     
    Bruce Berquist likes this.
  17. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,133
    50,050
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    that's a great idea! she might need a picture of the white plug and description.
     
    Bruce Berquist likes this.
  18. Fifine

    Fifine Member

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A


    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

    Joined:
    May 14, 2012
    7,855
    3,967
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    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

    Joined:
    Aug 15, 2014
    106
    20
    0
    Location:
    So Cal
    Vehicle:
    2008 Prius
    Model:
    N/A
    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
     
    Bruce Berquist and bisco like this.