How to reset battery to turn off check engine light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by hbomb232, Feb 2, 2010.

  1. hbomb232

    hbomb232 New Member

    Nov 24, 2009
    2003 Prius
    Hi everyone,

    I have a 2003 Prius with about 125k miles on it (original owner here!), and the check engine light came on while I was on my way to work today. The last time it came on a few months ago, a non-dealer mechanic said it was the O2 sensor, but that he reset the battery. If the light didn't come back on in a few days, I shouldn't worry about it. It didn't, so I didn't. Well, like I said, that was a few months ago and now the light is on. I'd like to reset it myself to save some money. If it comes on in a few days, I'll take it in to Toyota, but I'd like to try this reset button magic myself, first. :) Can anyone tell me how to do this?

    PS - I'm sorry if this isn't the right place to ask, but I didn't see a forum for 2003s and older. Please forgive me!
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Mar 8, 2008
    Green Valley, AZ
    2015 Prius
    Disconnect the negative battery cable for 5 minutes, then reconnect.

    BTW, you'll find the Gen 1 subforum within the Gen 2 Main Forum, if you should have other Qs in the future.
  3. fgoodyear

    fgoodyear New Member

    Aug 28, 2007
    Tillson, New York
    2007 Prius
    Take it to Autozone or Advance or one of the auto parts stores that have a code reader you can use and follow the simple instructions to hook it to your OBDII connector under the dash and clear it yourself. With engine off, plug the code reader into the OBDII plug, turn on the reader, WITHOUT your foot on the brake, push the start button to get it on accessorie, code reader will work and show codes, it will then ask if you want to clear codes, do what it says, probably hit CLEAR button. A lot of them look different but do the same thing. After it is done, shut it off and disconnect the reader and try it. You should be cleared then. My daughters Honda Accord has an O2 sensor that acts up every once in a while, so I do this to hers.