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Malfunction Indicator Lamp and others

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Mauiman, Nov 21, 2017.

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  1. Mauiman

    Mauiman Junior Member

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    2011 Prius, driven regularly. Today went out to leave home, pressed button to start and got full dash board lit up with warning lights, such as the malfunction indicator light, the electric power steering warning light, the brake system warning light. If I recall, The shift indicator was in "P" and flashing and would not shift out of park into any gear or neutral.
    I tried to turn off the system and it would not turn off - only after multiple attempts it did turn off.
    I turned on again, and again got multiple warning lights. Eventually after fooling around with on/off and gear shift level, I got it to shift to neutral and the engine started but was spitting and sputtering as if it was running on only half its cylinders. I got it to shut off again after several tries.
    I don't know what's going on - would the 12v battery cause all this mayhem? or some dead fuses? or???
    But in the owner's manual, it says for the malfunction indicator light, do not drive the car and get it to the dealer to check it out. My local dealer can get to it for a week. In the meantime, any thoughts on cause(s)?
     
    #1 Mauiman, Nov 21, 2017
  2. Travis Decker

    Travis Decker Active Member

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    Order a mini vci off Amazon, get techstream going, scan car post results
     
    #2 Travis Decker, Nov 21, 2017
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  3. bisco

    bisco cookie crumbler

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    start with the 12v, low hanging fruit.
     
    #3 bisco, Nov 22, 2017
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Amen, that should be a mantra. Oh, it is, lol.

    Original battery?

    Also, how many miles on the car?

    Do you have a digital multimeter? If not get one, measure the voltage with the car off. If the car's got diagnostic screen, resist the urge to use that, use the multimeter.
     
    #4 Mendel Leisk, Nov 22, 2017
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  5. Mauiman

    Mauiman Junior Member

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    Yes, it is original battery. The car has 44,000 miles on it. I don't have a digital multimeter, but can get one.
     
    #5 Mauiman, Nov 22, 2017
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    If you a drawer with bunch of dubious condition AA batteries, you can check those too, it'll pretty much recoup the cost of a cheap meter. Invaluable for lots of stuff: small appliance wiring checks, making sure the power's off when doing any household outlet repairs. If you have deeper pockets, google Solar BA5.
     
    #6 Mendel Leisk, Nov 22, 2017
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  7. jerrymildred

    jerrymildred Senior Member

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    Sounds like the 12V battery given the age and the symptoms. But definitely check it before replacing it.
     
    #7 jerrymildred, Nov 22, 2017
  8. bisco

    bisco cookie crumbler

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    44,000 miles over 6-7 years is around 6-7,000 ,lies per year. between the age and amount of driving, it might be the problem.
     
    #8 bisco, Nov 22, 2017
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  9. Mauiman

    Mauiman Junior Member

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    Checked 12v aux battery with multimeter - seemed to indicate between 8.5-10 volts. Then, after switching to Accessory mode for 10-20 seconds then On mode, the dashboard lit up with warning lights again, then the warning lights went out and the Ready light lit and the engine started - it ran very rough for 10 seconds or so and then ran seemingly correctly and smooth. I could again shift gears. I dared to drive the car around a couple of blocks and back home. I don't know if the problems "fixed themselves" or if the 12v battery is still very weak and won't hold a charge or not. I'll try again tomorrow and see what's up. May just end up getting a new battery. I don't really know what to think about the 8.5-10v reading on the multimeter - a failing battery?
     
    #9 Mauiman, Nov 24, 2017
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Measure a new 9V alkaline battery with your meter, and the measurement should be around 9.6V. This establishes that your meter is working.

    Then if your measurement of the 12V battery really is below 12V, replace it now.
     
    #10 Patrick Wong, Nov 24, 2017
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  11. jerrymildred

    jerrymildred Senior Member

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    What @Patrick Wong said.
    99.999999999999999% chance you need a new 12V battery.
     
    #11 jerrymildred, Nov 25, 2017
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  12. JC91006

    JC91006 Senior Member

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    If you don't replace it, at the very least, go get it charged
     
    #12 JC91006, Nov 25, 2017
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  13. Mauiman

    Mauiman Junior Member

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    Well, I did test a 9V battery as Patrick suggested and my multimeter read 9.5v so it seems the meter is working OK. Given that the 12V aux battery read between 8.5 and 10V, I think its time to get a new battery. Since the car is 6 yrs old and it is the original battery, it has lasted longer than I had planned on.
     
    #13 Mauiman, Nov 26, 2017
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  14. bisco

    bisco cookie crumbler

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    well done!(y)
     
    #14 bisco, Nov 26, 2017
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah google "the 12 volt side of life", for a site with some battery info, including a little chart of 12 volt battery voltage and corresponding state-of-charge. It's maybe a little dated, with AGM batteries which supposedly have slightly higher values, but still a good reference. Here's that chart:

    upload_2017-11-26_8-10-52.png
     
    #15 Mendel Leisk, Nov 26, 2017
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  16. Mauiman

    Mauiman Junior Member

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    Dealer checked it out - it only threw one code "U0155 - lost communication with instrument cluster ECU"...Battery drawdown was well within specs and didn't point out anything really wrong with 12v battery. We let the car sit overnight and mechanic checked in morning - the aux battery had lost voltage while sitting overnight and we replaced the aux battery. All seems to be going OK now - no warning lights, no multiple tries to get Ready light to come on and be able to shift, etc. So, assuming this problem is over. Got 6+ years out of the battery which I consider pretty good.
     
    #16 Mauiman, Nov 29, 2017
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  17. bisco

    bisco cookie crumbler

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    congrats, well done!(y)
     
    #17 bisco, Nov 29, 2017
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  18. JC91006

    JC91006 Senior Member

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    Did you just pat yourself on the back?
     
    #18 JC91006, Nov 29, 2017
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  19. Raytheeagle

    Raytheeagle Senior Member

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    Someone has too:whistle:.
     
    #19 Raytheeagle, Nov 29, 2017
  20. Fostel

    Fostel Member

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    I had the Malfunction indicator lamp this morning. It was a rough idling.
    malfunction_indicator_lamp.jpg
    I quite panicked as yesterday I cleaned the K&N engine air filter (after 20K miles) and housing, been removing mass air flow sensor too - all was fairly clean.
    Last week I did the oil change myself.

    When I went back home I checked what the user manual is saying
    malfunction_indicator_lamp.jpg
    A quick search here and found a possibility that the 12V battery is aging.

    Facts:
    My car is late 2013 so the auxiliary battery is 6 years old.
    The car is 71K miles at the moment
    Last night was very cold around 2 degrees Celcius
    Last night I did some car hoovering (12V 120W hoover) so I discharged battery a bit.

    When I came back after 10 min of driving the light did not pop up.
    I measured the 12V battery afterward:
    system OFF: 12.72V
    system ON (but not ready): 12.51V
    engine ON (charging): 14.64V so it works too.
    I need to test the battery when the car is left not used for a few days I suppose or after a cold night to see if the battery still holds the charge, especially that I am going to hardwire a 2 camera dashcam to it pretty soon.
    Anyone would shed some light (previous posts maybe) about:
    1. What 12V battery to get? Recommendations? Any third party (same spec) or Toyota genuine only?
    2. What code reader/ reset tool to purchase? (the car is European, the UK made model).

    Thanks.
     
    #20 Fostel, Apr 14, 2019
    Last edited: Apr 14, 2019
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