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Check engine light on, then off--data stored?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bnprius, May 15, 2023.

  1. bnprius

    bnprius Junior Member

    Joined:
    Aug 21, 2007
    20
    3
    0
    Location:
    Ypsilanti Michigan, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    My 2007 Prius, which we've had since new, recently showed the "check engine" symbol for the first time ever. It was on for several days, then went off & stayed off.

    Does anyone know if it has saved a code as to the problem which it indicated? I've scheduled a visit to my Toyota dealer to have them check it.

    Also, does anyone know what problem areas the "check engine" light covers? Is it just for the gasoline engine, or for the entire hybrid system?

    Now at 180,000 miles, my Prius has recently been making a growling sound, which varies with the driving speed (becoming a howl at highway speeds). The sound starts suddenly and stops after a few seconds, apparently at random. It makes the sound once in several days. Does anyone have any idea what's causing this? Would the "check engine" light indicate a problem in the drive train, such as in the transaxel?

    Thanks for any help you can give me on this.

    Bill in Ypsilanti MI
     
    #1 bnprius, May 15, 2023
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,307
    15,098
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    A code considered "current" makes the light turn on. If the condition then isn't detected in some number of drives, it stops being a "current" code, and the light goes out. For many codes, it will still be around as a "permanent" code that will show on a scan tool, but not light the light. "Permanent" codes, despite the name, do eventually go away, if on the right number of consecutive drives the car runs the monitor test associated with the code and gets a passing result. So if the light was on fairly recently, there should be a pretty good chance the permanent code is still in there.
     
    #2 ChapmanF, May 15, 2023
  3. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,097
    5,810
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    It could suck if Toyo charges you $175 to do a diagnostic just to tell you your gas cap was loose.

    Any chance of just running by a NAPA or AutoZone to have them check your DTC memory?
     
    #3 TMR-JWAP, May 15, 2023
  4. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    8,102
    1,399
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    I have found my Inova branded I think it's 3120 or 3520 so $39 scanner Menards and advance Auto sell it It has a red button for ABS codes That's how I tell it apart from other models this little portable silly scanner has made it so I rarely have to pull my text stream the fujitsu CF-13 laptop off the shelf and charge and use It's rare now so that little Innova scanner has saved me a lot of hoo ha as far as having to run out to cars with a booted military grade laptop just to read codes.
     
    #4 Tombukt2, May 16, 2023
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