Questions about the red triangle warning light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Aranthon, Jun 29, 2016.

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  1. Aranthon

    Aranthon Junior Member

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    Hi all,

    I have an 06 Prius with about 170k miles. The hybrid battery was replaced shortly before I bought the car last year.

    About a month ago, the red triangle warning light started coming on when I'm stopped. It usually stays on for a few seconds once I start moving again. The MFD just says "Problem" for a few seconds, then displays the icon for a headlight. Once the light clears, the MFD goes back to its normal display. Originally, it was lighting up once every other day or so, but now it's lighting two or three times per trip. I'm going to have to do something about it, but I'm trying to get my head around what to expect.

    My understanding is that the red triangle could mean anything from "The door is open and you're moving. Please close it." to "Your car is about to melt down! Seek cover!". I have an Automatic OBD dongle, and it's not reading any diagnostic codes. But as I understand it, there's a whole different set of diagnostic codes that a "regular" OBD reader won't catch.

    I keep seeing reference to ScanGauge devices -- do they read the second set of diagnostic codes? I talked to a mechanic in the area who will read the codes for about $100. Is the mechanic likely to be reading the codes with that tool/is that what a dealer would use to read the codes? Is the dealer likely to charge to read the codes?

    Thanks,

    Greg
     
    #1 Aranthon, Jun 29, 2016
  2. S Keith

    S Keith Senior Member

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    Don't drive it again before you check your oil and top it off. As they increase in mileage, they start to burn oil. It's critical you keep it between the marks on the dipstick.

    Do not overfill.
     
    #2 S Keith, Jun 29, 2016
    Last edited: Jun 29, 2016
  3. edthefox5

    edthefox5 Senior Member

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    Although very good advice to check your engine oil if the engine was low on oil it would throw a check engine light. Your seeing a master caution alarm which is hybrid related.
    The Scangauge will only read Hybrid codes if it has been upgraded to an Xgauge. If you own a Scan you can send it in and for $25 they will upgrade it to an X.
    If it was me I would get the codes pulled asap. When a Prius throws a master caution alarm its not kidding. Its warning you that your about to take the bus.
    Yes a dealer will charge a minimum of one hour labor to pull the codes. Around here for instance thats $145.
    Wherever you get the codes pulled make sure they are written down including the subset code and then post them back here and we can tell you exactly whats wrong with your car. Don't fall for any dealer hyperbole until we can see the codes.

    Until then limit your long distance driving if you can.
     
    #3 edthefox5, Jun 29, 2016
  4. Priusyipee

    Priusyipee Active Member

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    The key here is that the OP is stating that the MFD is showing the headlight icon. A simple fix. If you have HID headlights, the headlight leveling sensor is failing and should be either taken out and repaired or replaced. Historically, the sensor's o-rings and casing have not held up to the weather in order to prevent the intrusion of water. The contacts corrode and you will begin experiencing problems. Yes, the red triangle does appear with the word "problem" and the icon showing the headlight symbol on the MFD. Scared me to death when it first happened with my '05 Prius back in 2009!
     
    #4 Priusyipee, Jun 30, 2016
  5. bisco

    bisco cookie crumbler

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    take it to toyota if you want the codes read properly. should be about the same cost.

    how many miles on her?
     
    #5 bisco, Jun 30, 2016
  6. jadziasman

    jadziasman Prius owner emeritus

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    Priusyippee knows what the problem is. A headlight leveling sensor malfunction will light the icon on the MFD and the red triangle of death. There is no DTC that I'm aware of for this error. I had this error pop up four months after I bought my 05 Prius back in Oct 2010. I struggled with DIY repairs for a year and eventually got a new harness connector and sensor from a recycler.

    I replaced the harness connector and the sensor in 2012 and it hasn't given me trouble since EXCEPT the leveling sensor arm/lever that attaches to the torsion beam broke in the middle - I don't know how long ago - maybe last winter. I noticed this today when I rotated the tires. Luckily the sensor did not get damaged and what remains of the lever is fixed in place (undoubtedly it is rusted solid even though I applied silicone sealant in the area). Road salt eventually finds a way in though. What a PITA device.
     
    #6 jadziasman, Jun 30, 2016
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