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2007 Prius suddenly won't start.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Dustin Lowe, Jul 30, 2023.

  1. Dustin Lowe

    Dustin Lowe New Member

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    Hello All,
    I am trying to troubleshoot my daughters 2007 Prius. I have linked a video that shows exactly what it's is (or isn't) doing.
    About a year ago, the car was hit by a drunk driver while parked and rather than total the car, the insurance "fixed" it. Well, it's never been the same since. I know, SHOCKER! Well, the MFD stopped working but thats another issue. They recently drove it from San Diego, CA to Central Texas where they now live near us. It's been running just fine but the other day, my daughter came out to drive it, and it wouldn't start. Day before it was running fine.
    I checked all fuses but nothing bad found.
    I tried to jump it, but nothing happened.

    Here is what it's doing:
    1-Key inserted, it makes some buzzing sound and then the beeper starts beeping.
    2-Foot on brake and hit start button, nothing happens except the light on the start button goes green but no dash lights.
    3-Hit the Start button again, Light on the button turn red and all warning lights come on but no start.

    If I turn it off and try it again, same process happens but the motor will not start.
    The 12 volt battery is brand new and reads charged.

    They have already put a bunch of money into this car so I am trying to get it going for them for cheap but I worry that it could be a sign of a more expensive problem. Any assistance would be greatly appreciated.
     
  2. JC91006

    JC91006 Senior Member

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    First check to make sure 12v is actually good. Then if it is, it seems like your brake switch switch is bad. It can't determine that the brake is pressed, so you can only get into accessory mode.

    Or it's possibly you have a high voltage isolation fault. If you disconnect the 12v battery negative terminal (that's the easiest disconnect) for a few seconds, and reconnect, see if the car will start. If it'll start 1 time and the same problem occurs again, then you probably have the high voltage isolation fault.
     
  3. Dustin Lowe

    Dustin Lowe New Member

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    So, by the Brake switch, do you mean the Brake Light Switch that releases when you depress the brake or is there another switch I should look at because that seems like an easy check.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    Is the car getting the ready sign are you readying the car? When you say no start what do you mean by that are you expecting the engine to fire right up the minute you get the lights on? You say you have no speedometer or display does it come and go or has it been off now for months? So that means usually to turn the car off you've got to hold the start button in for a few seconds and watch the car die? These are important things to kind of know
     
  5. Tombukt2

    Tombukt2 Senior Member

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    In your video when you have all the dash lights on that's accessory mode That's like where you'd bleed the brakes and stuff. So you hit the button one more time and now everything is off and I'll put your foot on the brake and just hit the button don't hold it touch it one time and get your finger off of it nothing happens at all You don't see ready obviously not I guess because that's what happened the first time you did it that is interesting You have no way to scan the codes I take it?
     
  6. JC91006

    JC91006 Senior Member

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    yes brake light switch
     
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    I'd do a quick check to see if the rear brake lights illuminate when the pedal is pressed, but that switch may have separate contacts, I just don't remember.

    Does it do the same exact thing if the brake pedal isn't pressed?

    Not likely to be a P0AA6 since there's no RTOD (master warning light).
     
  8. dolj

    dolj Senior Member

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    That is not accessory mode (ACC), it is IG-ON. The first button press is ACC.
    I notice you're pressing the button for a second time and holding it for several seconds. What happens if you just press it quickly like you do for the first press?
     
  9. Tombukt2

    Tombukt2 Senior Member

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    So what mode is that in his video with all the lights on it looks like the two button pushes without the brake pedal being pushed brings up all the lights and whatever so that's ignition or accessory It's like turning the key to the first step My scanner will work in this mode where it won't when the display is not on I don't think I'll have to check it again after bleeding this weekend you get to realize all this really quickly I don't see the ready logo so the car is on but not ready and the shifter will move to neutral and back to park and that's it so I'm guessing he can't get to ready and of course can't drive. I'm not sure what everybody means by start usually they're trying ready the car so they can go forward or backwards and be on their way but the engine is not going to start until you put it in gear going backwards or forwards and depending upon how low the battery is and how fast you're trying to go sometimes backing up in my driveway at first ready in the morning I can back up 150 yards if I'm not killing the gas pedal and then the engine will start just as I'm getting ready to throw it into drive or right as I'm doing so The engine will start I guess the start charging the big battery and off we go but if I don't see ready we're not going anywhere.
     
  10. Dustin Lowe

    Dustin Lowe New Member

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    Same thing seems to happen. I have tried for different lengths of time and always the same.
     
  11. Dustin Lowe

    Dustin Lowe New Member

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    So, the car will not shift into D or R. Just goes to Neutral and back into park.
     
  12. Dustin Lowe

    Dustin Lowe New Member

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    OK, so trying the easiest thing first...
    Checked and I have NO BRAKE LIGHTS! Also, the car acts the same whether I depress the brake pedal or not when trying to start it so a new switch is on order. Daughter had one of those AHA moments when I explained this to her and she said that she had noticed some weird starting issues over the past several months that she just thought were "quirks" or something but just never added them up to this bigger problem. Fingers crossed that a $16 switch fixes it for them. I will update if this fixes the problem or if there is anything else.
     
  13. dolj

    dolj Senior Member

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    IG-ON.
     
  14. Dustin Lowe

    Dustin Lowe New Member

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    So, I have gone through all 3 of these options.
    12 volt seems good it’s been sitting a few weeks now but still reads 12.1v at the battery and under hood.

    Changed the brake switch with a new one, no change and still no brake lights when the pedal is depressed. Checked all fuses that I could find associated with brakes and they are all good. Also noticed that the brake indicator on the dash stays on no matter if it’s depressed or not. This is troubling. Anything else I should be checking in regards to the brakes?

    Disconnected the battery like you said to check high voltage isolation, but everything is still the same.
     
  15. bisco

    bisco cookie crumbler

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    rodents?
     
  16. Dustin Lowe

    Dustin Lowe New Member

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    No evidence of such.
     
    bisco likes this.
  17. ColoradoCrow

    ColoradoCrow Active Member

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    Does the key fob LED light up when you press it? unlock and relock the doors? Do you have another key fob to try? What other quirks did she describe? Is the Hybrid battery original? With only 123K miles I assume it is the original Traction battery.
     
  18. bisco

    bisco cookie crumbler

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    if the brake lights won't come on, i think i'd concentrate on that, make sure the switch is making contact and there's voltage on both sides when activated.

    of course, scanning the troublecodes with tech stream would be best.
     
  19. ColoradoCrow

    ColoradoCrow Active Member

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    If it sat in Texas heat for a few weeks and the 12 volt battery is at least 2 years old.....I'd pull it and have it load tested at an auto parts store. Just don't close the rear hatch.Put a towel or floor mat over the latch so it doesn't latch to avoid having to crawl in the back.
    I also assume you don't hear the relays clicking in the rear drivers seat cushion area on the top of the Hybrid battery? Normally There are 2 clicks as the relays to the HV battery open.as the car goes into READY MODE.
     
  20. Dustin Lowe

    Dustin Lowe New Member

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    So, they have 2 key fobs and both produce the same results. Neither one will open the locks though. Could it be a problem with the key programming maybe?

    I am pretty sure it is the original Hybrid battery as well. I was wondering if that might be the issue but it seemed to stop all at once. I am not familiar with Prius' but this didn't seem right. One day it was running, the next it was not.

    EDIT: I checked her other key fob and the light does illuminate and it will lock/unlock doors but I still get the same result from trying to start it.
     
    #20 Dustin Lowe, Aug 5, 2023
    Last edited: Aug 5, 2023