Outside temperature gage fluctuates

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Chad Pettingill, Oct 5, 2012.

  1. Chad Pettingill

    Chad Pettingill New Member

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    Hi All,
    Long time reader, first time poster.

    Something strange started happening to my '04 Prius yesterday and it happened again today. We are experiencing unseasonable warm temperatures here in Western Oregon for October and when I left my house this morning at 6:30am, it was about 55 degrees. I have a half hour drive to work on a mixture of expressway, freeway, expressway again and then two-lane highway.

    Anyway, yesterday (and today) when I'm almost to work, my temp. gage drops down to 37 degrees. This causes that yellow light to start blinking indicating that the engine will not shut off becaues of cold temps. It will warm back up to 45 degrees a minute or two later. Why is this happening? It for sure is not 37 degrees outside. Is my temperature sensor going bad? Is this exhibiting the behavior of a sensor going bad?

    Any input would be appreciated. Thanks!
     
    #1 Chad Pettingill, Oct 5, 2012
  2. uart

    uart Senior Member

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    Sorry I don't know the answer to your question about the outside temperature sensor. Unless there really was some much colder air/wind out on the road compared to your 55 degrees at home then I suppose it must be a sensor issue.

    I'm pretty sure however that the yellow light is just the "snowflake warning" isn't it. I think it's just to warn you that you cold potential strike and icy patch, not that the engine can't cut out.
     
    #2 uart, Oct 5, 2012
  3. Britprius

    Britprius Senior Member

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    It is possible this is caused by corrosion on the connectors to the sensor. The sensor is mounted in front of the radiator on a vertical support and is easy to get at. The sensor does feed OAT to the engine ECU but I do not believe it will affect how the engine runs to any great degree.

    There have been obscure reports of the temperature misreading but this is usually reading high because the grill is blocked (for winter) or the aircon fans have been installed the wrong way round after damage repair.
     
    #3 Britprius, Oct 5, 2012
  4. koolingit

    koolingit Member

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    If the temperature sensor gets wet, it will get colder than the actual temperature. Depending on how low the relative humidity is, it can get a lot colder. Don't ask how much -- I'm not that bright. If it was raining or you were driving through puddles, this could be normal behavior.
     
    #4 koolingit, Oct 6, 2012
  5. Chad Pettingill

    Chad Pettingill New Member

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    Thanks for the replies. It actually wasn't raining out when this happened both times. I will keep monitoring it's. Although if it does this every day, could lower my gas mileage. I'll keep you up to date. Thank you!
     
    #5 Chad Pettingill, Oct 7, 2012
  6. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    Sometimes connections get dirty and may cause a problem like the one you are having. I recommend you locate the sensor, unplug it, and clean the connections with QD electronic cleaner. Most auto part and hardware stores have it (at least around here, anyways).
    IMAG1011.jpg
     
    #6 Avi's Advanced Automotive, Oct 8, 2012
    koolingit likes this.
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