Hybrid Synergy Drive Warning Light in Very Cold Weather

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by HM_Prius, Jan 2, 2011.

  1. HM_Prius

    HM_Prius New Member

    Jan 2, 2011
    Winnipeg, MB
    Your Vehicle Year:
    2004 Prius
    In Canada, car is stored outside. Temperatures are in the vicinity of -20 to -30 centigrade. I do have an engine block heater.
    2004 Toyota Prius.

    Started up Prius.

    Steering column stiff and PS (Power Steering Warning light) and Hybrid Synergy Drive (HSD) warning light were both on. Triangle with exclamation is also on.

    Engine appears to be running fine. After 20 minutes in the sun, and running the engine the PS light is now off. HSD Light and Triangle! are still both on. Drove it around the block, energy appears to be moving as normal between battery pack, engine and electric motor.

    Steering is no long sluggish.

    Manual says not to drive and to contact dealer for service immediately.

    I have cycled the engine off and on for 20 minute periods three times, the warning lights are still on.

    THis problem occured once before in the evening and the following day at 11am it was not happening. I assumed it was due to cold whether which had lessened in the interval.

    I am curious if there is some other lubricant inside the electric motor that could be frozen or partially frozen causing this warning. I also thought perhaps the power steering fluid froze causing that warning. I don't think its likely that the engine block heater (which is primarily intended to keep the engine's oil from freezing) is enough to keep other parts of the electric motor and engine from getting too cold in winter.

    Has anyone else experienced this problem?

    Can I drive this car today or is the HSD, and Triangle! lights a really severe warning? ie is this like a "check engine" light that means it needs service or is this a "holy crap you are out of oil and burning up your engine RIGHT NOW!" sort of warning light.

    thanks for your help
  2. jdenenberg

    jdenenberg EE Professor

    Nov 21, 2005
    Trumbull, CT
    Your Vehicle Year:
    2004 Prius
    First check your 12v battery voltage. Do it with the Prius off and no load and then turn on the lights to see how low the voltage drops. The voltage should stay above 12v in both conditions. A weak 12v battery can cause multiple symptoms.

    If you don't have access to a meter, put the Prius in "Maintenance Mode". Instructions can be found at several places.

    1. Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10 where you can also order a good 12v battery.
    2. http://priuschat.com/forums/gen-ii-prius-main-forum/57853-maintenance-mode-battery-voltage.html
    3. Checking 12v Battery Health - Hybrid Car Forums
    4. Etc.
  3. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Oct 2, 2004
    Your Vehicle Year:
    2010 Prius
    I was gonna say that the power steering fluid is frozen (as you described a similar scenario when we started up my friend's 1999 Camry in -40 degree whether. It was like the steering shaft was dipped in molasses) but the Prius' steering is electrically assisted so AFAIK, there isn't any power steering fluid. It's possible that some electronics were frozen.

    I had a rather loud and harsh vibration in my car last year after leaving it outside for two weeks in -20C weather when the car was shifted into D.
  4. usbseawolf2000

    usbseawolf2000 HSD PhD

    Sep 22, 2004
    Fort Lee, NJ
    Your Vehicle Year:
    2012 Prius Plug-in
    Plug-in Base
  5. B. Roberts

    B. Roberts Hypah Milah! Ayuh.

    Mar 11, 2005
    "Glacial" Maine
    Your Vehicle Year:
    2011 Prius
    Wonder what the coldest weather anyone had actually driven their Prius. Since we bought ours in March of 05, we have only dropped to around zero to 5 degrees below zero one time, and the car did fine. We haven't had a really cold Winter in some time.

    Any stories out there?
  6. GigaTigga

    GigaTigga New Member

    Nov 19, 2007
    Your Vehicle Year:
    2005 Prius
    I recall some stories of people in northern Canada with temps in the -20s to -40s iirc

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