Help Prius with Master warning light + vsc + brake system

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jigsaw99, Jan 7, 2012.

  1. jigsaw99

    jigsaw99 New Member

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    2005 Prius
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    I have a 05 Prius w/ 71mi>. I bought it almost 1.5 yr ago from an accident repair used car store that specializes in Priuses and selling to taxi companies. I had no problem with the car and have kept up with general maintance it since i bought it. Only thing I replaced was the tires to all weather.

    The problem: I was driving a parking lot when Master warning light went on along with multiple warning lights (i don't rememer which was on). I quickly pulled in the vehicle over to the side and powered it off. When I tried to turn it on again - the car won't start. This was on new years eve and late at night so I got a friend to pick me up since I needed to catch my new years party and thought i deal with the problem tomorrow morning. The next day, I phoned my dealer and he told me to disconnect the 12vbattery in the back and replugging it. It worked. The car starts with no warning lights + everything worked like it did before. I drove it to my dealer with no problem and he told me that he'll do a diagonistic on it with the computers and get back to me.

    Couple days later I picked my car up and my dealer told me that he drove it and did computer tests and cannot find anything wrong with it. None of the warning lights went on - Nothing. I am fine with this and thought this maybe an one time thing and is glad I don't have to pay to fix anything. The car seemed fine and had no problems on the long drive home. However, the day after the warning light went on again. I drove home and turned it off and un-plug/replug the battery again and to start the car again. I drove it for about a min and the warning lights came on (Master + VSC + breaking system malfunction). Now it is not a one time thing. Everytime i can get the car to start by repluging the battery on the warning lights goes on immediately.

    I phoned my latest Toyota dealer to get their opinion and they told me that it could be a tracking system malfunction or an computer/electric connection problem... the diagonistic can cost anywhere from 100-300 bills. My dealer told me he would look at it again and try to find the problem for me and lend a company car. I am going to try to see if my dealer can solve this and if not I'll take it to Toyota and have them look at it.

    I really hope it's something small like a 12v battery replacement... I've only had the car for 1.5 years and don't want to have to pay for a large repair cost.
     

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    #1 jigsaw99, Jan 7, 2012
  2. jpadc

    jpadc Type before I think too often

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    Welcome to PC jigsaw99:

    Many here will tell you that a weak / going bad 12 volt auxiliary battery can cause many odd things to happen in the car like the warning lights you have seen. Its possible that is the cause and replacing the 12 auxiliary battery will solve your problems. If you even suspect its bad, you should replace it.

    Likely the dealer could not find any codes when they did a diagnosis earlier was that they were lost when the 12 volt battery was disconnected. Once the dealer is able to read error codes, you should ask them to tell you what they are and post them here. There are many very experienced members here who can help you sort through the best, and likely least expensive options towards a fix.

    Sorry, but no one here will likely loan you a car, so part of the diagnostic fee is at least getting you something.

    Bob
     
    #2 jpadc, Jan 7, 2012
  3. a_soccer_player

    a_soccer_player Junior Member

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    I had something similar when I still had my '08 back when I lived in Hawaii.

    I came to a stop getting ready to turn into a parking lot when the same lights came on. Plus it felt like there was constant pressure being applied to the brakes when the car moved.

    Long story short, dealer looked into it, found that a bad 12v battery had caused a surge to fry my brake chip. It took like three days to get the part out to Hawaii. Luckily, the replacement chip and battery were free since the car was still under warranty.

    Hopefully it's just the 12v battery in your case.
     
    #3 a_soccer_player, Jan 7, 2012
  4. priusNlondon

    priusNlondon Pingu 2.0

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    That's what mine did when the cells went bad in my Traction battery. I luckily was still under warranty so they replaced it.
     
    #4 priusNlondon, Jan 7, 2012
  5. seilerts

    seilerts Battery Curmudgeon

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    Every time you disconnect the 12V battery, it erases the diagnostic codes stored in the HV ECU, ECM, etc. The fact that you can disconnect the 12V battery and the car restarts without VSC and Brake warning lights means that the problem is likely within the hybrid system, rather than with the brake system. It could be anything from the inverter cooling pump, A/C compressor, transaxle or HV battery. What you need to do is have the codes read, or have the car towed to the dealer, the next time the fault occurs.
     
    #5 seilerts, Jan 7, 2012
  6. richard schumacher

    richard schumacher shortbus driver

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    #6 richard schumacher, Jan 7, 2012
  7. jigsaw99

    jigsaw99 New Member

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    The first time it happened when I reconnect the 12v the warnign lights went away but now the lights are on everytime I manage to start the car.
     
    #7 jigsaw99, Jan 7, 2012
  8. nai1ed

    nai1ed 2006 Prius

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    I am having the exact same problem. I notice those lights come on when I accelerate from a standstill. I ordered a new Optima battery, hopefully that will fix it.
     
    #8 nai1ed, Mar 6, 2013
  9. Jack2929

    Jack2929 New Member

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    Hello. I'm having exact same problem with my Prius, and it has new 12V battery. Did you happen to fix your problem?
     
    #9 Jack2929, Jul 31, 2015
  10. bisco

    bisco cookie crumbler

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    welcome! i suggest starting a new thread, and detailing your car history and problem experience in full. all the best!(y)
     
    #10 bisco, Jul 31, 2015
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