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2006 Electrical Issue - Can I rule out the 12v?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jimsjimsjims, Jun 14, 2013.

  1. jimsjimsjims

    jimsjimsjims New Member

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    I have a 2006 with 200k miles. The only issue I've had with it is that the remote died a few years ago and I have been driving key-in-slot since then. Then, this morning, the MFD refused to boot and the car refused to turn on.

    Some basic diagnostic stuff:

    -Interior dome and door lights work, as do the headlights and break lights.
    -Battery connections in trunk are tight.
    -Pullable fuses all fine, main 100 amp fuse seems undamaged.
    -No recent power problems, still getting 40+ mpg.
    -Trickle charged the 12v with a 1.5amp charger until it stopped accepting current (3 hours or so)
    -Pressing start without key-in-slot brings up the familiar "no key" symbol.
    -Pressing down on the break pedal causes the familiar grown from the engine compartment.
    -Pressing the power button with the key in does nothing, whether the break pedal is down or not. No reaction whatsoever.

    Because the headlines seem strong and other lights are working my next step was going to be unhooking the ground connector to reset the computer.

    Two questions:

    1. Will I erase any diagnostic data by resetting the computer, thus making it harder for the dealer (should I need to take it to them) to diagnose any problems?

    2. Am I ruling out a 12volt problem too early?

    -Jim
     
  2. bisco

    bisco cookie crumbler

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    welcome to priuschat! 200,000 troublefree miles? nice.(y) i wouldn't rule out the 12v until you've tested it. but at 6-7 years old, i would replace it anyway, before you get stranded somewhere.
     
  3. Riaz

    Riaz Junior Member

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    Maybe the key FOB battery is dead.
     
  4. cwerdna

    cwerdna Senior Member

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    Please run the test at Weird stuff happening? MPGs dropping? Test The Battery | PriusChat after the car has sat MANY hours or overnight (or you can use a voltmeter). Please tell us the 3 values (not just 1). Don't go changing the battery first until you tell us the values...

    If you have HIDs, you can avoid unnecessary cycles on the lights by toggling between off and parking light positions.

    Weird stuff can start happening w/a low or bad 12 volt. Don't waste $ on having a dealer "test" the 12 volt (07 Prius Dead - Any Guesses? | PriusChat). If you're on the original 12 volt, it's likely at end of life now.
     
  5. ahmeow

    ahmeow Prius Lover

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    I also recommend to check the Fob battery. How long is the battery in there? Or have U ever change the 2013 3Volts lithium button battery inside?
     
  6. cwerdna

    cwerdna Senior Member

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    Sure, check the fob battery, but the Prius should be able to be put into READY mode w/a dead fob battery if the key is in the slot. That's what the slot's for.
     
  7. jimsjimsjims

    jimsjimsjims New Member

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    -The key FOB or its battery are most certainly dead. I've been driving without it for a while with no trouble.
    -I can't currently get into ACC mode (mfd not coming up at all) to run the diagnostics listed in the thread that cwerdna linked to, but I'll run a voltmeter off of the 12v in the morning and see what values I come up with.
     
  8. Britprius

    Britprius Senior Member

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    This is a little difficult with the MFD not working and the car ECU's not booting. The only check that can be done is with a volt meter off load. The headlamps will not work unless the car can be booted into accessory mode, and the car will not show the charging voltage without being made ready.

    John (Britprius)
     
  9. Riaz

    Riaz Junior Member

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    Does the LED indicator on the power button light when you press power with brake depressed or does it remain off? what color does it show if it does light?

    Assuming the 12v battery passes, it sounds like the RFID chip in the Key fob may have failed although that's probably uncommon. Has anyone else ever experienced FOB failure?
     
  10. jimsjimsjims

    jimsjimsjims New Member

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    Update:

    Battery tested out at 12.61 in volt mode and 12.69 in battery test mode.

    I Disconnected the ground for 10 minutes to no effect.

    I just tried jumping the car off of my friend's battery to no effect.

    John: The headlights and break lights are all working even though I am not in ACC mode.

    Riaz: The led indicator on the power button comes on slightly when I put the key in the slot or open and close the door, but doesn't react at all to being pressed, whether or not the break is depressed. If I take the key out of the slot I get the "no key" symbol on the dash when I press the power button.
     
  11. bisco

    bisco cookie crumbler

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    maybe you should replace the key fob battery just for kicks.
     
  12. jimsjimsjims

    jimsjimsjims New Member

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    Update:

    Replaced the key fob battery. Remote now works as it did a year ago, but there was no effect on getting the mfd to boot.

    Also, I went through a general check and found that the coolant levels were low. The main reservoir was well below minimum and the upper reservoir was just above minimum. I topped them off, but I don't see how that would have any effect on the computer/electrical issue.

    Anyways, I'm going to swap out the aux battery in the morning just in case.
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That being the case, I suggest you also remove the radiator cap and check the fluid directly in the radiator. You will need to remove the plastic cover over the radiator by removing the six plastic fasteners.

    You earlier posted that you measured 12.6V at the 12V battery. If that is an accurate measurement then battery replacement probably won't help.

    You might need to seek professional assistance on your no-start issue now that you've ruled out simple issues.
     
  14. Riaz

    Riaz Junior Member

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    Barring an issue with the Transponder chip inside the fob or with electrical connectivity to the keyslot (there's a snap in connector at the back) then theres probably an issue with one of the ECUs or power to it and you will need expert assistance as Patrick recommended.

    A couple more suggestions to rule out the simple things:

    1. If any work was done in the past that required disassembly of the part of the dash with the power button and keyslot, then remove the panel and make sure the electrical connectors at the back are snapped in all the way.

    2. You've probably already done this, but try the other key fob if you have 2.
     
  15. jimsjimsjims

    jimsjimsjims New Member

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    Quick update:

    Car was towed to a dealer. They have tried various fixes related to FOBs without success and are moving on to testing control modules.

    Riaz: The dash hasn't be disassembled...



    ...before now :(