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Gen 2 ECB Warning Light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Brycefw, Dec 29, 2023.

  1. Brycefw

    Brycefw New Member

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    I need some help determining why my Master Warning Light (triangle of death) and Electronic Controlled Braking lights are coming on (circle with !) in my 2nd gen Prius. I have a cheap OBD2 code reader that isn’t showing anything. I took it to AutoZone; they couldn’t determine the problem. I took it to my local Toyota dealership, so that they could use the TechStream software; still nothing showed. I’m at a loss. I attempted to use the Flash method via the C4 and C13 short pin connections on the OBD2 connector. The flashing dash lights didn’t reveal anything either.

    I’m ready to throw in the towel. I can’t drive anywhere without clearing the “code” first, even though no code exists. I’ve spent $2K in the last month trying to find a solution. The hybrid battery is less than two years old. The 12V is brand new. The inverter coolant pump is new. The catalytic converter is new. Fluids are topped off. What else could it be? I replaced the computer module with a used one from eBay, but that didn’t help either.

    The car is a 2007 model with 275K miles on it. Is this a losing battle? Should I cut my losses, or is there a fix for this issue? HELP!
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Somewhere here in this forum somebody will be along in a minute and give you a link there's the complete manual for this car It sounds like you need to go through some of those troubleshooting steps and they are extensive long long long process possibly but something is going on so when you reset the codes with your cheap scanner does that turn off all the lights including the!? That's interesting and the Toyota dealer told you there's nothing showing in tech huh That's even better I wonder if they're actually connecting but I would hope so it's not that difficult.
     
  3. ChapmanF

    ChapmanF Senior Member

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    If you let us know what codes they flashed, maybe they'll reveal something to us.
     
  4. Brycefw

    Brycefw New Member

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    The flashes didn’t indicate any codes. They were all consistently rhythmic—no changes or deviations.
     
  5. Brycefw

    Brycefw New Member

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    Yes, my cheap scan tool can “erase” the codes, even though no code displays. It turns off the (!) and Master Warning Lights, but they return as soon as I start the car.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    Yes if I'm not mistaken this is real common when you have the code for the battery leaking the HV battery leaking voltage to the rest of the car I just went through this I use my cheap scanner I clear the codes twice then I can drive the car when I turn the car back off under most conditions it will not restart sometimes it will a couple of times a day but usually not and I can't remember what that code is but it's the one for HV battery isolation fault sometimes you will have the green car and the MFD displaying is red I am not sure if your cheap scanner can tell whether the inverter coolant pump is bad or not working or what have you but usually you can hear that running.
     
  7. Tombukt2

    Tombukt2 Senior Member

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    The reason it's making you clear the codes in order to start the cars because that's a pretty serious or could be a pretty serious problem so it makes sure that you know it not making you clear the codes even with the inappropriate scan tool somebody just happened to figure that out I don't know who and it doesn't matter but HV battery voltage which is around 211 plus or minus volts running to the frame of your car is not a good thing.
     
  8. Brycefw

    Brycefw New Member

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    I just had the inverter cooling pump replaced.
     
  9. Tombukt2

    Tombukt2 Senior Member

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    Right and I don't think that's one of those things you can erase the code twice and keep driving You can erase the code for the inverter coolant pump and keep driving or even keep driving with the code and the car in the MFD instead of being green it'll be red If you get too hot it just throttles back and doesn't charge as well but the car will still run fine with the HV battery isolation issue that can get possibly dangerous so me thinks they don't want you just clearing that code and driving so they make it so you can clear it move the car anytime you turn the car off you're going to have to clear the code again they figure most normal people aren't going to have that capability so you may want to look into the HV battery isolation issue It's pretty easy to test with the voltmeter and you'll just be pulling the plastic out of the trunk for a minute accessing the orange high voltage disconnect plug You going to measure from that disconnect plug while it's plugged in and the cover is off from a top or bottom bolt on that fuse to the frame of the battery case You're looking for ideally zero volts If your battery is leaking you'll show volts on this meter with your probes touching like constructed It will never zero because the battery is leaking voltage that is and it could also be leaking electrolyte type stuff onto the tray
     
  10. ChapmanF

    ChapmanF Senior Member

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    VOIDH