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Heavy rain triggered Red Triangle and check engine light. How to proceed?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ryan R, Dec 28, 2022.

  1. Ryan R

    Ryan R Junior Member

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    2008 Prius
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    There has been lots of rain this season, and last night my car triggered its red triangle warning after driving over a smallish puddle. The car was driven for 2 hours on the freeway prior in the rain with no issues. After the light, it drove home fine and did not lose any main features.


    Can exposure to water cause a false alarm red triangle? The undercarriage has a broken splash shield. The 12V was replaced around 1 year ago. Car is 2008 w/ 181K miles, original battery.


    I stored it inside garage overnight to dry off but still has the lights displayed nearly 14 hours later. If the water causes a false battery light, could I just unplug the 12v to reset the lights and monitor the car going forward? Taking this car into the mechanic could be a electrical rabbit hole and cost $$$$


    Thanks!
     
  2. ChapmanF

    ChapmanF Senior Member

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    It's a big distraction to try to guess what turned the warning light on. Just find out. A dealership will have a scan tool that will tell you the trouble codes, but some mechanics may too. Or you can look for the apps that can get you that info, here:

    Gen2 OBD2 app review | PriusChat

    You didn't say there's a lot of stuff wrong with the car, so I'm not seeing how visiting someone with a scan tool to find out why your warning light is one would turn into a $$$$ rabbit hole.

    What'll happen is you'll know why the light's on. Then we can talk about whether that'll be $$$$ or not.
     
  3. Ryan R

    Ryan R Junior Member

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    That will be my best course of action. I was mostly curious if this is a common issue that could be adverted without seeking any mechanical help. I'll get a free scan and hope for the best
     
  4. ChapmanF

    ChapmanF Senior Member

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    Be careful with the free scans. There are a lot of ECUs in a Prius, including several that many generic scan tools won't even know about or show you the codes from. The trouble codes that can light the master warning triangle are found in a couple of those ECUs.

    So what usually happens in a thread like this when somebody has that light is there'll be a later post where they say "ok, had it scanned, there aren't any codes", and then some posts after that where we say "nah, if the light's on there are codes, that scan tool just didn't show them", and so on.

    So if you go by a place that offers free scans and then they tell you there weren't any codes, you'll know you need to visit somewhere with a better scan tool (or equip yourself with one, which the thread I linked above can help with).
     
    Ryan R likes this.
  5. swooshrc

    swooshrc New Member

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    Did you fix the common cracks in the upper corners of the hatch opening?