Coworker's Prius: Engine rarely shutting off after 04/05 TSB on stalling was applied. Related?

Discussion in 'Gen 2 Prius Fuel Economy' started by 2k1Toaster, Sep 9, 2011.

  1. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,855
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    So I got to be the passenger in another Prius for the first time today. It is an 05, not sure of the mileage on the odometer. 12v has never been changed, has been jumped at least once.

    However he is fairly sure that his engine not turning off problems are related to the firmware flash for stalling. If you recall, the 04 and some 04 built 05's had a HV ECU reflash to address the issue that it could stall randomly. Immediately after that reflash, his engine almost always runs and his mpg's have decreased.

    Since the reflashing obviously changed the HV ECU and how it reacts to the engine and battery with different variables, it seems plausible that this could be related.

    He says that sometimes when he shifts to park at a traffic light, this will allow the engine to shut off whereas normally it would just keep running. While being a passenger I noticed that after warmup sitting at a stop light the engine was definitely running when in mine it would not be.

    Does anyone have a list of things that changed during the TSB update? Does it take variable X more into account or something like that?

    The reason I suspect the other "normal" factors less is that he claims it happened almost immediately after the TSB update a couple years ago and has never been the same since.
     
    #1 2k1Toaster, Sep 9, 2011
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    113,819
    51,802
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    my flash worked fine on my 04, not that i was having any problems before. can a flash go bad? what's he getting for mpg's?
     
    #2 bisco, Sep 9, 2011
  3. cwerdna

    cwerdna Senior Member

    Joined:
    Sep 4, 2005
    12,544
    2,124
    1
    Location:
    SF Bay Area, CA
    Vehicle:
    2006 Prius
    I'd have that 12 volt changed ASAP first. As we all know, a 12 volt of that age us likely bad.
     
    #3 cwerdna, Sep 9, 2011
  4. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,518
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    +1 on the 12V. They are supposed to hook up a backup power supply when applying the flash, but perhaps they did not and drained the battery.
     
    #4 seilerts, Sep 9, 2011
  5. SiRealiUS

    SiRealiUS New Member

    Joined:
    Aug 26, 2011
    2
    0
    0
    Location:
    So. Cal.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    What is thy typical life expectancy of the 12v? We just got a 2007 with less than 35,000 miles and it doesn't exhibit any symptoms of the OP, so I don't think we need one, yet. But, if an 05 or 06 would be long in the tooth 12v battery-wise, then obviously a 07 isn't far off.

    Here's one thread I found answering this question (had to remove 'http' because of current posting privileges):

    //priuschat.com/forums/gen-iii-2010-prius-care-maintenance-troubleshooting/97157-12v-batterys-life-expectancy.html

    Short answer: 3-5 years
     
    #5 SiRealiUS, Sep 9, 2011
  6. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,855
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    I am aware the 12v should be changed. The problem however seemed to arrive immediately after the flash and I am wondering what that flash actually did. The 12v would have only been 2 years old at most then.

    There were times during our city drive that the engine 100% should have shut off and didn't. It kept running and running.
     
    #6 2k1Toaster, Sep 9, 2011
  7. 2009Prius

    2009Prius A Wimpy DIYer

    Joined:
    Mar 25, 2009
    2,705
    512
    63
    Location:
    USA
    Vehicle:
    2009 Prius
    Get PriiDash or Torque set up and record the engine coolant temperature, vehicle speed, and engine RPM. Post the result here and we can analyze. Good luck!
     
    #7 2009Prius, Sep 10, 2011
(You must log in or sign up to post here.)