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Readiness monitor errors after engine swap on 2007 prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Monte Lewis, Nov 30, 2022.

  1. Monte Lewis

    Monte Lewis New Member

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    I just completed an engine swap on my 2007 Toyota Prius with 300K miles. I got the new engine in fine, but got a catalyst monitor, evaporative system, and oxygen sensor readiness monitor error when I went to restart the car. Car will not start in this condition. My thought was that maybe some of the wiring got messed up during the swap. Are there any schematics of the wiring for the vehicle that would help me determine if some of the sensor signals aren't reaching the ECU? It would be nice to verify the cause before I go changing components.
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Were there any OBD2 codes that you could post?

    FYI : you're moderated until you've posted 5 times.
     
  3. mr_guy_mann

    mr_guy_mann Senior Member

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    What OBD device are you using to scan the car?
    What are the exact errors reported, and are there any DTC's (diagnostic trouble codes)?

    Posted via the PriusChat mobile app.
     
  4. Monte Lewis

    Monte Lewis New Member

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    I've used two OBD scan tools to check for errors. One is called DashCmd and the other one is called Torque. Using the torque tool I am able to see coolant temperature, battery voltage, and throttle position, so it seems like I'm getting comms. Neither tool is showing any fault codes. The status of the readiness monitors is incomplete, I guess because I had the power disconnected from the car. When I start the car I get the car symbol with the explanation point on the touch screen. Typically when you start the car you hear all of the relays engage and the car starts. I am not hearing any of those clicking relay sounds at the moment, just the immediate explanation point symbol. I have the car completely off the ground on jack stands at the moment.
     
  5. bisco

    bisco cookie crumbler

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    is the 12v healthy?

    did you disconnect the orange safety plug?
     
  6. Monte Lewis

    Monte Lewis New Member

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    Yes, I did have that disconnected while I was working. I plugged the connector back in upon completion and have tried removing and reinserting it. I also disconnected some cables from the inverter during the work but reinserted them. I didn't take out the inverter during the engine swap. The 12V battery looks good. I was thinking to try the Techstream tool to try to get some more detailed diagnostics.
     
  7. ChapmanF

    ChapmanF Senior Member

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    'Incomplete' emissions monitors do not prevent the car from starting or running. They just remain 'incomplete' until you have driven enough to have hit all the right conditions for the monitors to run, and then they change to 'complete' and tell you whether they passed or failed.

    So if the car isn't starting or going READY, that's because of something else.

    Some scan tools will not show you trouble codes from all ECUs in the car. If there's an immediate exclamation point, there are codes to see, but you might be using a scan tool that doesn't show you those.
     
  8. Monte Lewis

    Monte Lewis New Member

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    Yes, I am going to try the Techstream tool from Toyota to try to find out what problem it has. The OBD tools I have on my phone (DashCMD and Torque) do not indicate any error. It will take me a couple of days to get the equipment, but I'll try it then.
     
  9. SFO

    SFO Senior Member

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    For torque, did you load the required gen2 PIDs ?
     
  10. Monte Lewis

    Monte Lewis New Member

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    I’ve loaded some of those I think. My hybrid battery went out this year and I was troubleshooting it with the Torque app. I used it to see the voltages of all the cells in the battery pack. I don’t know if there are some specific ones to download for this problem.
     
  11. mr_guy_mann

    mr_guy_mann Senior Member

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    When you plugged the orange safety connector back, did you slide the handle down until it clicked? (3 steps; insert plug, swing handle/lever in, slide handle down). This is a commonly overlooked step - at least the first time!

    Both of those scan apps are VERY limited on a Prius. They have codes, data, & "performance" functions based on generic OBD2 info from the ECM (engine computer). Nothing additional for Toyota or Prius ECM.

    Torque (Pro) can enable data (and some codes?) for the hybrid system. But that's all- there's 15 or 16 ecu's total on a Gen2 Prius.

    Techstream is one option. You can also read this thread about scantool apps and devices to find something more capable.
    https://priuschat.com/index.php?posts/3290690


    Posted via the PriusChat mobile app.
     
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  12. Monte Lewis

    Monte Lewis New Member

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    I’ll try reinserting the orange plug a couple more times using the technique you described. I think I may not have slid that top handle down.
     
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  13. Monte Lewis

    Monte Lewis New Member

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    I resolved this problem by making sure to follow the technique for inserting the hybrid battery safety connector as described above by mr_guy_mann.
     
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  14. bisco

    bisco cookie crumbler

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    you're welcome :p
     
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