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

Why is my alarm going off?

Discussion in 'Gen 2 Prius Main Forum' started by GuamKelly, Mar 23, 2011.

  1. GuamKelly

    GuamKelly Member

    Joined:
    Sep 17, 2010
    274
    68
    0
    Location:
    Ipan, Guam
    Vehicle:
    2008 Prius
    Model:
    III
    Twice today, and a couple other times since I've owned the car, I've reached for and opened the door and immediately had the alarm go off. Totally blows one's Cool Dood image. It seems it only happens when I'm in a hurry. Also, I THINK the clock is resetting to 1:00 when it happens (will re-check when and if it happens again). Any ideas? Am I doing something wrong, or is this a malfunction?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,479
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    This implies that you have a problem with the 12V battery. I suggest that you measure battery voltage after the car has been resting overnight.
     
  3. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,663
    1,039
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
  4. GuamKelly

    GuamKelly Member

    Joined:
    Sep 17, 2010
    274
    68
    0
    Location:
    Ipan, Guam
    Vehicle:
    2008 Prius
    Model:
    III
    I'll have a look this morning Patrick -- pretty odd though, as I just installed a new Optima a few months back in an effort to forestall any 12V battery problems! Perhaps the clamps are loose or corroded . . . or the brounding strap. I'll let you all know what I find.
     
  5. GuamKelly

    GuamKelly Member

    Joined:
    Sep 17, 2010
    274
    68
    0
    Location:
    Ipan, Guam
    Vehicle:
    2008 Prius
    Model:
    III
    After sitting overnight, "Vehicle Signal Check" showed the 12V (an Optima, approximately six months old) battery at 12.4 Volts. When I placed a load on the battery it indicated 12.1 Volts, and when I placed the car in "Ready" mode it was charging at 13.9 Volts. All that seems to be within the normal range, correct?

    Later, when the sun is up, I'll have a look at the terminals and at the end of the negative lead where it attaches to the battery. Any other ideas on the OP?
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,479
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The battery voltages seem OK although a bit low. The battery might benefit from an overnight charge.

    Yes, it would be good to check the tightness of the electrical connections at the battery as well as the negative cable where it bolts to the body. Hopefully you'll find a problem.
     
  7. GuamKelly

    GuamKelly Member

    Joined:
    Sep 17, 2010
    274
    68
    0
    Location:
    Ipan, Guam
    Vehicle:
    2008 Prius
    Model:
    III
    That was exactly the problem. I must have under-torqued the positive cable clamp when I installed the new Optima kit, and it had loosened significantly. Tightened it up, all appears well, will do cold voltage check again tomorrow morning. :D