Prius 2014 Not Starting

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by jamadon, Mar 22, 2023.

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  1. jamadon

    jamadon New Member

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    First time poster here. Having a problem with my 2014 Prius that I'm desperate to solve. I purchased the Prius about five years ago and started experiencing this problem perhaps two years ago. Basically, when I press the start button, all the dash lights come on, but only a thin line square appears around the P (park) on the dashboard, and the car cannot be shifted into start. It just beeps when you shift. When the car is functioning properly a thick, broad square appears around the P. When this glitch occurs it takes multiple efforts, sometimes up to 20, to start the car. I just keep turning it off and on until the proper light around the park signal shows up indicating that the car will go into drive. This tends to happen intermittently, but gets worse over time. The problem is, I've taken the car in for diagnostics 4 times. Twice to the dealership and twice to another mechanic. Though they too will experience the issue, no codes ever show up indicating any problem with the car. It sure seems like a drain to me, but they can't seem to find any evidence of a drain. We've gotten new fob batteries to rule that out. The one thing they've noticed is the erratic behavior of the 12v battery. It will test out perfect one day but not the next day, and jumping it does solve the issue....for a few days. Though I strongly believe the issue with the 12v is a symptom and not a cause, it's the only possible explanation any of the mechanics who have looked at our Prius have been able to suggest. As a result, we have had our 12v changed out twice (we're on our 3'rd). Each time, the Prius will start perfectly....for a time, and then the same behavior will start up again. We just changed the 12v maybe 5 weeks ago, and yesterday the starting issue resurfaced. We're just at wits end. I have very limited knowledge about cars. We have a problem that numerous mechanics have seen for themselves, but are completely baffled as to the cause. And again, no codes ever come up in diagnostics. Any help here would be greatly, greatly appreciated! Thank you!
     
    #1 jamadon, Mar 22, 2023
  2. ChapmanF

    ChapmanF Senior Member

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    It might be interesting to see, maybe, first-thing-in-the-morning voltage readings from the 12 volt battery, on a series of mornings, stretching from when it's new and everything works perfectly for a time, and through that time, and up to when it begins acting up.
     
    #2 ChapmanF, Mar 22, 2023
  3. bisco

    bisco cookie crumbler

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    Might be too much drain on the 12v when the car is off, or, you might not drive it enough to keep it charged
     
    #3 bisco, Mar 22, 2023
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Sounds like parasitic draw discharging the battery. Usually most obvious after the car has sat overnight or longer. When you drive it the hybrid system quickly recharges the 12v battery with 30 or more amps.

    A kluge fix is to keep the battery on a $35 battery maintainer at night. I like the Battery Tender Jr widely available from Walmart to Amazon. A quick connect cable allows you to permanently install it on the battery while leaving the plugin charger outside.
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    One thing about dealer mechanics. Many are not "master mechanics" or even certified. Often the best and most experience start their own shops. Service advisers are usually not mechanics and are really just smiling faces on commission. It sounds like you need a shop with parasitic draw expertise who will keep it overnight or over the weekend in order to test it properly. Although the same shop should be able to measure the draw anytime. There may be a module that is weak and fails under slightly reduced voltage or a marginal connection in the 12v feed.
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    #4 rjparker, Mar 22, 2023
  5. jamadon

    jamadon New Member

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    We do drive it a lot, so I'd be surprised if that's the issue. What would be draining the car when it's off?
     
    #5 jamadon, Mar 22, 2023
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  6. bisco

    bisco cookie crumbler

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    it can be anything with a bad connection. very difficult to track down unfortunately.

    but a good meter can detect the amount of drain with the car off
     
    #6 bisco, Mar 23, 2023
    Tim Jones likes this.
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