Engine will not start, CEL/MWL.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Armicron, Jul 4, 2020.

  1. Armicron

    Armicron Junior Member

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    I'm at my wits end on this and need some help.

    Car was sitting for a period of about 24 hours, after attempting to turn on the car I got the always unhelpful and misleading "Christmas Lights" (Master Warning Light, Brake, CEL, ABS, etc). Radio and air would turn on but the engine would not.

    Doing a quick diagnosis I found that the 12V was not at an appropriate charge, I replaced the 12V but still have the problem. Here's what I've already tried:

    • Replaced 12V Battery (Yes, double-checked polarity, 3 wires, and whatever that "tube" is)
    • Reviewed fuses under the hood
    • Checked Fluids (All fine)
    I have two and only two codes when I attempt to start the car, C1259 and C1310. I know this is not a problem with the Hybrid battery itself. (Just trust me on this one, I've replaced the Hybrid Battery in the car twice, I know the symptoms.)

    I can only assume there is some connection issue I'm missing but I have no clue where. People mention some sort of bolt or wire or something super-vague in other posts but I have no idea what they could be referring to.

    Plz Halp.
     
  2. SFO

    SFO Senior Member

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    What does the 12v read when using a voltmeter at the jump points under the hood?
    Have you checked the attached negative cable/ground strap from the 12v battery to the body of the vehicle for corrosion and tightness?
     
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  3. Elektroingenieur

    Elektroingenieur Senior Member

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    As the Repair Manual (more info) explains, those DTCs are both “output from the skid control ECU when the hybrid control ECU sends a malfunction signal to the skid control ECU,” which implies that the hybrid control ECU should also be reporting a problem.

    Can the diagnostic software and hardware you are using to read the DTCs actually communicate with the hybrid control ECU? For example, with a Toyota Techstream diagnostic system, can you access the Powertrain > Hybrid Control > Data List screen and read the “Num of Current Code” and “Num of History Code” items and see the ON/OFF status of the three system main relays?
     
  4. Armicron

    Armicron Junior Member

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    I'm getting 11.9V when powered on. Doublechecked the connections to the posts, the 3 plastic plugs, and both ends of the negative terminal. They're all tight.


    Unfortunately no. It is super basic. I'm wondering if the battery was drained completely previously if there's some other way to reboot the system aside from unplugging the 12V.
     
  5. SFO

    SFO Senior Member

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    Are you still using techstream?

    And after resetting the 12v the vehicle won't start, but will still scan and retrieve DTCs C1259 and C1310 ?
     
  6. Armicron

    Armicron Junior Member

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    Yep, I've got a crappy little OBD reader. I used to have a copy of TechStream but it no longer functions at all. But right now, when I start it, I only get those two codes. I know the OBD reader is capable of getting the "P" codes, but not any of the proprietary sub-codes.
     
  7. SFO

    SFO Senior Member

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    It may be time to upgrade/downgrade to an OBD2 adapter and an App like Torque or Dr Prius.

    Use this link to help pick out a compatible device : Hybrid battery diagnostic and repair tool for Toyota and Lexus

    We might be able to get you back into techstream again, do you still have a mini-vci cable and a device with a USB port?
     
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  8. Elektroingenieur

    Elektroingenieur Senior Member

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    If it’s a generic OBD II code reader, made for engine and emissions diagnosis, it can probably retrieve Pxxxx (powertrain) DTCs from the engine control module, but not from the hybrid (vehicle) control ECU or battery ECU. As @SFO kindly notes, you need a Techstream system or equivalent.
     
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