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Warning lights

Discussion in 'Newbie Forum' started by Lodrun, Jan 27, 2018.

  1. Lodrun

    Lodrun My proper car is an MGC

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    I have a Prius series 2, 2007. A couple of times recently a selection of warning lights has suddenly come on when driving (not including the big triangle of death) accompanied by a fairly quiet warning bleeper. The car continues to drive normally. When I power off, wait, then power on again, all is well for another few weeks, then it happens again. Any ideas?
     
    #1 Lodrun, Jan 27, 2018
  2. bisco

    bisco cookie crumbler

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    check your 12v and fob batteries, but without trouble codes, it's tough to diagnose.
     
    #2 bisco, Jan 27, 2018
  3. Elektroingenieur

    Elektroingenieur Senior Member

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    Even if we knew which warning lights were appearing, it would be difficult to make a diagnosis without more information. In general, warning lights mean one or more of the car’s electronic control units (ECUs, i.e., on-board computers) has detected a problem, and when this happens, the ECU typically stores a diagnostic trouble code (DTC) in its memory.

    You could use a Toyota Global Techstream diagnostic system, or third-party equivalent, to view these stored DTCs. Toyota’s Repair Manual, available by subscription to toyota-tech.eu, has a detailed explanation and troubleshooting procedure for each DTC; use this information to evaluate likely causes and make repairs.

    Note that generic scan tools made for engine and emissions diagnosis may not be able to communicate with some of the car’s ECUs, such as those related to the hybrid system, so they may not find all of the DTCs.
     
    #3 Elektroingenieur, Jan 27, 2018
  4. Beachbummm

    Beachbummm Senior Member

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    brake warning lights are the only ones I know of that set off a buzzer.(of course I could be wrong).. I had a bad connection to the drivers side abs sensor .. water got in and caused the problem..
     
    #4 Beachbummm, Jan 27, 2018
  5. Beachbummm

    Beachbummm Senior Member

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    your signature should be
    "Have you checked your 12 volt?? "

    ;)
     

    Attached Files:

    #5 Beachbummm, Jan 27, 2018
  6. bisco

    bisco cookie crumbler

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    it would be, if i knew how to add one.:cool: seems to be the biggest problem with prius.
     
    #6 bisco, Jan 27, 2018
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  7. Lodrun

    Lodrun My proper car is an MGC

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    Thanks for your replies. Aux battery indicates 11.9 to 12.1 V using the built-in self-test feature. My local Toyota agent says that if the fault is clearing itself there will be no diagnostic codes to read, as they will also be cleared. Not sure whether this is true.

    I am interested in Beachbummm's theory about an abs sensor. I seem to recall that some of the warning lights were brake related (the park brake warning was definitely one of them). Was your bad connection at the front caliper? And are there sensors on all four wheels?

    Thanks, again.
     
    #7 Lodrun, Jan 28, 2018
  8. bisco

    bisco cookie crumbler

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    you definitely need a new 12v, even if it isn't the problem.

    or, you could try charging it, and see if it holds a bit higher, say 12.3 or 4.
     
    #8 bisco, Jan 28, 2018
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  9. jdenenberg

    jdenenberg EE Professor

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    Bisco,

    Click on your ID (top right of screen) and then click on "signature" in the left hand column.

    JeffD
     
    #9 jdenenberg, Jan 28, 2018
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  10. Lodrun

    Lodrun My proper car is an MGC

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    You could be right. The car was left standing for 3 weeks when we were away recently and when we returned the 12V battery was completely flat. I trickle charged it for 7 hours and all was well again. I was not unduly worried as I believe that the security system draws 0.07 Amp from the battery when the car is standing, which is about 35 Amp-hrs over 3 weeks. But maybe it went flat much quicker than that.
     
    #10 Lodrun, Jan 28, 2018
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  11. bisco

    bisco cookie crumbler

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    thanks doc!(y)
     
    #11 bisco, Jan 28, 2018
  12. SFO

    SFO Senior Member

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    How many miles, and when was the battery last changed/serviced?

    How much time does the vehicle spend in 'ready' mode when used on a daily or weekly basis?

    How many amps is the trickle charger you used?

    The parking brake warning is also indicative of low voltage.

    Codes are generally stored even if auto cleared, dealer may be wrong.
     
    #12 SFO, Jan 28, 2018
    Last edited: Jan 28, 2018
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  13. Beachbummm

    Beachbummm Senior Member

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    when you look behind the wheels you will see a 2 wire harness running to each one, thats the sensor wires... the sensor is just a magnet picking up a signal as the wheel spins.. mine was getting moisture inside the connector, i dried it with a heat gun then sealed it with some silicone "caulk" .. you can also remove the sensor and clean it.. if i remember right its held in with one bolt.. then again that could be my GM van.. its been a while
     
    #13 Beachbummm, Jan 28, 2018
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