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P2118 Throttle Actuator AND Red triangle light? Help!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JoeVR, Oct 8, 2020.

  1. JoeVR

    JoeVR Junior Member

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    Hi everyone,

    I'm new to this forum, and I have a frustrating mystery that I hope you can help me solve.

    I have a 2004 Prius that is throwing a P2118 code. If I disconnect the 12v battery for a few minutes then reconnect, it will run just fine for about 5-10 seconds (accelerator working just fine), then the red triangle light will come on, the car will throw a P2118 code, and the accelerator pedal will stop working. The car will idle just fine, and using my Dr. Prius app, the pack voltage will read 200 volts, with average blade voltage of 7.17. I realize that is kind of low, but I thought the car should still drive. It has sat for over a year, so maybe that's why.

    How can I tell if the throttle actuator control motor is bad? Is there a way to figure out if the problem is in my pedal or in the throttle body? Or is this happening because the voltage is dropping too low?

    Any help would be so greatly appreciated. I'd love to get this back on the road. The P2118 code is mighty scary when you lose all pedal functions. Thank you all!
     
    #1 JoeVR, Oct 8, 2020
  2. PriusCamper

    PriusCamper Senior Member

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    Perhaps @SFO can post the write up for that error code? He's good at that!
     
    #2 PriusCamper, Oct 9, 2020
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    If your average module voltage is 7.17, your battery is seriously depleted. Like, depleted to the point it's almost useless.
     
    #3 TMR-JWAP, Oct 9, 2020
  4. SFO

    SFO Senior Member

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    #4 SFO, Oct 9, 2020
    Last edited: Oct 9, 2020
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  5. PriusCamper

    PriusCamper Senior Member

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    That'd be a fairly normal voltage after failing to start the engine too many times...
     
    #5 PriusCamper, Oct 9, 2020
  6. ChapmanF

    ChapmanF Senior Member

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    #6 ChapmanF, Oct 9, 2020
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  7. SFO

    SFO Senior Member

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    #7 SFO, Oct 9, 2020
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  8. JoeVR

    JoeVR Junior Member

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    Thank you all so much.

    Yes, I really exhausted the battery. I pulled out the battery and went through the painstaking process of charging each module up to 8.4v using an RC charger with a NMH setting. The charges all seemed to hold at 8.0v, so I reinstalled the battery. I drove it just fine for about 200 yards with the throttle control working perfectly, then the red triangle light came on, and I lost all throttle control. The engine would still idle, but I had no throttle control.

    I'm wondering if I have a double problem - ECM and hybrid battery? If I were to replace the ECM, would I have to use one from the same year prius?

    I'm pretty new to the prius scene, so I appreciate everybody's help with this. Many thanks!
     
    #8 JoeVR, Oct 12, 2020
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    I'm pretty new to the prius scene,

    And unfortunately, this is part of the problem. We're very likely speaking different languages right now. What you consider idling could be idling, or it could be the car trying to start the engine and failing. The Prius does not have a standard 'starter motor' system. When you press the power button(with foot on brake), the car should go ready. After several seconds, the HV system will apply power to the transaxle, spinning the engine for start. It spins it fast enough that most people think the engine is running. If the engine starts, it will run long enough to do part of it's warmup routine and then turn off again (unless you put it in gear and start driving, then it will do its hybrid thing). If it fails to start after several seconds of spinning, it will try again. If it fails again, it will code out.

    I guess I just don't fully understand what you mean by losing throttle control.
     
    #9 TMR-JWAP, Oct 12, 2020
  10. JoeVR

    JoeVR Junior Member

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    Yes, you are correct. I assumed that the "idling" was an actual idle. I can feel the prius drop into gear when I put it into drive, but my accelerator pedal still doesn't work . . .

    The pdf posting from the technical manual was incredibly helpful. I did all the tests and they all checked out. Voltage was between 9 and 14, so I don't think it was the ECM. The wires also ohmed out, so I'm pretty sure there isn't a short in any of the wiring.

    If I disconnect all batteries for a bit of time, and reconnect, it will work for about 20 seconds before the red triangle light pops on, and the check engine light comes on and I lose throttle response.

    If there is something else that I should be checking, I'm willing to go for it. Any other ideas would be so appreciated. Thank you all!
     
    #10 JoeVR, Oct 13, 2020
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    Does the car come out of 'ready' when the RTOD triggers?

    This is going to be one of those times where it would be advantageous to have Techstream. It pretty much has unlimited ability to provide information about what's going on with the car. It also can provide tons of freeze frame data from when a code triggers, so you can see exactly what the conditions were. Techstream is available online, you just need a laptop and a cable.

    That being said, I helped someone over the summer who had very similar symptoms, but this car had a handful of issues going on, including a failing ABS module.. We didn't have a lot of time to play, and swapped in a salvage yard throttle body, the relay that mounts to the side of the inverter (this relay opens the main HV battery relays if any airbag is sensed to have triggered) and we replaced the HV battery with a quick rebuild I had laying around. Problem GONE. (except for the abs).
     
    #11 TMR-JWAP, Oct 13, 2020
    Last edited: Oct 13, 2020
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