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Hymotion White Wire to ECM -What's it for?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Lithium, Jan 12, 2009.

  1. Lithium

    Lithium HyMotioned Member

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    I recently had the HyMotion kit installed in my Prius (lucky me) and have a question?

    Some background
    Prior to having the kit installed, I hooked up the CoastaleTech EV mode kit. As I'm sure most everyone knows, the CoastalTecThe switch basically pulses pin 27 of connector H17 to ground on the Hybrid vehicle control ECU if the cruise control stalk is pulled for a few seconds. After I wired in the EV kit, I used it several times and it always worked fine. In other words, the car entered EV mode when it was supposed to (<35MPH & light acceleration & adequate SOC on the battery & etc.).

    The Problem
    Then, I had the Hymotion kit installed. Afterwards, the EV switch either doesn't work at all or it will enter EV mode and then immediately gets kicked out of EV mode. I confirmed this by connecting a Scangauge and monitoring the EV XGAUGE. It appears that Hymotion is toggling the car into and out of EV mode several times per minute. So, I snooped around on Priuschat and read where Hymotion taps into pin 27 of connector H17 on the Hybrid vehicle control ECU (the one closest to the psgr door). I then pulled out the glovebox on my car to confirm the wiring and discovered than on my car, the white wire coming from the Hymotion battery pack is NOT connected to pin 27 of H17. It is connected to pin 27 of connector E6 on the ECM (engine control module). I confirmed the pin number by wading through the Prius wiring diagrams.

    Can somebody please verify this: Connector E6 is the connector on the ECM that is closest to the floor. The ECM sits to the left of the Hybrid vehicle control ECU.

    It seems on my Prius, the way the white Hymotion wire is connected, it cannot directly control EV mode, but instead is somehow controling EV mode via the CAN bus.

    My Question
    For you others that have done a HyMotion install, where is your white wire coming from the HyMotion battery pack connected to -the ECM or the Hybrid ECU?
     

    Attached Files:

  2. hobbit

    hobbit Senior Member

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    First of all, I think it's H14-27 and that diagram is looking at
    the end of the *harness connector*, not the ECU. Someone's got
    things a bit backwards.
    .
    But it's pretty well known that the Hymotion kit runs a wire to
    the EV input and tries to manage it its own way, which causes
    numerous headaches for anyone who's a> already got a switch
    and/or b> already knows how to use EV mode better than the Hymo
    people tried to design what they do with it. Anyone already
    familiar with forced-EV mode would be way better keeping their
    own manual switch and chopping the Hymo connection.
    .
    _H*
     
  3. Lithium

    Lithium HyMotioned Member

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    Hobbit,
    Thanks for the quick reply.

    I know which connector and pin is H14-27 because I previously installed the EV switch and it worked successfully. H14 on the ECU is a gray connector. E6 on the ECM is a white connector. The ECU is the electrical box closest to the passenger door. The ECM is just to the left of that. Do you agree?

    The whire from my HyMotion pack is definitely connected to the white connector going to the ECM. I do agree with you that the view I show for the E6 connector is looking at the end of the harness connector. I just want to know if anybody else that has HyMotion installed has physically verified that the white wire is supposed to be connected to H14-27. I searched but could not find this confirmed in Priuschat. I suspect my installation may be incorrect.
     
  4. Lithium

    Lithium HyMotioned Member

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    I just took a a picture which clarifies the location of the Hymotion white wire connection in my vehicle.
     

    Attached Files:

    • ECM1.jpg
      ECM1.jpg
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  5. EZW1

    EZW1 Active Member

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    I'm not sure here, but it looks to me to be the wire that forces the car to run in elec mode only. Like the post above, it mus Hymotion's way of managing elec mode.
     
  6. Lithium

    Lithium HyMotioned Member

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    In the previous picture, you can see three wires (purple, white, orange) where the ends of them are covered in elec. tape and they are held in place with a yellow tie wrap. These 3 wires were for the CoastaleTech EV module that I have since removed because I thought it was causing issues with the HyMotion install. The orange wire on the EV module was connected to the ECU H17 connector, pin 27. I know the exact location of H17-27 because the EV module worked perfectly after I installed it.

    I have read about other HyMotion installs where the installer removed the CoastaleTech EV module to allow HyMotion to work correctly. What I'm hoping for is that somebody with a HyMotion installation can look behind their glove box and confirm where the HyMotion wire is connected.

    If all else fails, I could clip the white wire from the HyMotion install and connect it to H17-27 to see what happens. But I don't want to fry anything.
     
  7. PeakOilGarage

    PeakOilGarage Nothing less than 99.9

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    From my experience driving my Hymotion, no EV switch is required.
    I can control EV very easily with the gas pedal.

    The Hymotion software is making EV requests very often while driving. So if you are driving in a manner that permits EV mode, the Prius will shift into EV mode. Generally if the car is warmed up and below 40 mph, you will be in EV mode.

    I bought the EV switch, but I never bothered to install it because I don't see the need. Just my opinion.
     
  8. Lithium

    Lithium HyMotioned Member

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    PeakOilGarage,
    I partially agree with you that no EV switch is required with the HyMotion install. The one exception is if you want to force the car into EV mode when it's first powered on (to prevent the engine from starting). Putting the car into EV mode in this situation with a charged HyMotion pack is ideal when going on short, relatively slow (<35 MPH) trips.

    I currently have no EV button installed and with my HyMotion pack enabled, the car always starts the engine when I power on the car. At first, I thought it might be related to the ambient temperature. However, I have a heated garage, use the EBH, and have the heater turned off in the car. Does your HyMotion exhibit this same behaviour?

    Also, by chance have you popped out your lower glove box and traced the HyMotion wire to see if it goes to the ECM or the hybrid ECU?