Wouldn't start; replaced old 12V battery; now won't start again

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by zirconer, Feb 21, 2020.

  1. zirconer

    zirconer New Member

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    Last week in a cold snap in the Boston area, my 2007 Prius (150,000 miles) would not start. Despite driving a couple miles earlier in the morning, when I got in the car an hour later, the dash lights started blinking but nothing happened after that. Eventually, nothing lit up. No luck with a Weego portable jump starter, either. Fortunately I was able to get it jump started with a friend's vehicle, giving me enough juice to get home and park in my driveway.

    After reading some threads here, I purchased a new 12V battery at Autozone: a Duralast 46B24R-AGM that the Autozone website said would fit my vehicle. However, at the store they said the battery wouldn't fit because that battery is for the very common 2007 with SKS, whereas my car is an apparently rare 2007 without SKS. Indeed, the 46B24R was about 0.75" longer than the battery it replaced (an S34B20R), so I had to remove the bolts for the bracket that the battery normally sits on. In any case, I checked my old battery with a multimeter and it came back at 11.9V, and in my 6 years of owning the car I'd never replaced it, so it seemed I diagnosed the problem.

    On starting the first time with the new battery, I got the red triangle of death. But from reading these forums, that seemed somewhat typical after having no 12V for awhile. After a few more minutes, the car powered up and I was able to put it in drive without the RTD. I had to reset the automatic window, and the backup beep I'd previously disabled had returned, but that was it. I did notice that the Power button LED was amber on startup rather than green, but otherwise things seemed ok.

    After replacing the battery, my cousin drove the car ~50 miles and said it sounded loud; I'm including that anecdote here in case it means something. I planned on trying to reproduce that issue this weekend, but this morning was cold again, and the car did absolutely nothing when trying to start up - even the remote key fob could not unlock the doors.

    Has anyone experienced this before? My fears/suspicions are that it could be an issue with the hybrid battery, which has never been replaced (again, the car has ~150k miles). I don't think the new 12V battery could be the problem, unless having the wrong physical size also means its performance/specifications are also wrong for my non-SKS Prius.
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Any warning lights on the dash?

    What does the 12v read at the jump points under the hood?

    What codes (DTCs) did you retrieve when using a OBD2 code reader?
     
  3. edthefox5

    edthefox5 Senior Member

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    Don't like the "car sounds loud". That could be 2 things:

    Lots of catalytic converters getting stolen off G2 Pius's. There worth alot of money carb states like California the car will not pass inspection with an after market cat the oem cat is very $$$$. When they rip it off the exhaust system is basically removed so the car is very loud.
    very loud.

    And car sounds loud may be the hybrid battery is failing not providing any or low power and you really have to floor the engine to get it going. Engine is screaming just to get up and going.

    I suspect you may be right about the hybrid battery failing as it is very very common with our vintage cars. Mine started to fail 2 years ago but I have used the prolong system to charge and repair it. The mileage tanking is a real good hint. Thats stage 1 stage 2 is the RTOD and car goes into limp mode.

    Look at the mfd the screen above the radio does it have a little car icon in the top left corner we call the turtle. If you got the turtle its the hybrid battery.

    No turtle the OBD codes must be harvested by a Hybrid capable OBD scanner to see what the car is unhappy about.

    use the blue search forums selection up top and search HYBRID BATTERY to see what we are all gong through and your options.
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    I planned on trying to reproduce that issue this weekend, but this morning was cold again, and the car did absolutely nothing when trying to start up - even the remote key fob could not unlock the doors.

    Regardless of the condition of the HV Battery or the catalytic converters, the 12v battery should completely power up 12v ecu systems. If this is not happening, then there's a problem with the 12v system. Either the 12v battery is bad, it is being drained, or it has a loose connection or bad cable. That problem needs to be resolved, otherwise it's like trying to turn on your laptop with a dead battery (and no power cord). It just won't work...

     
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  5. eternalphoenix64

    eternalphoenix64 Junior Member

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    Have you checked the battery in the key fob?

    Just being sure......
     
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