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Where is the ECU Located in a 2001?

Discussion in 'Gen 2 Prius Technical Discussion' started by nuclear_j, Feb 10, 2009.

  1. nuclear_j

    nuclear_j New Member

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    I know it is begin the glove box and I have opened it. But I have no idea what it looks like. I imagined it to look like a large, square, fuse type thingy, but did not see anything like that. I did however see an air filter? It was pretty dirty. Is that the air filter to replace if you have starting issues? I should just replace it anyways.

    Well if anyone could tell me where the ECU is in relation to the air filter that would be awesome. And bonus points if you could direct me to a good site to order one.
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    There are several ECUs in any Prius.

    The cabin air filter is the one located behind the glove box. The engine air filter can be found in the engine compartment in the large black rectangular container near the front of that compartment.

    I suspect that you are referring to the engine ECU since you are talking about starting problems. That can be found after you lower the glove box down. Look into the opening, on the right hand side. You will see the engine ECU with multiple wire connectors attached to it.

    As to where to buy one, if you want to buy a new one and pay ~$1,000, you can order from one of the Toyota dealers that sell over the web; for example I buy from Champion Toyota in Houston.

    If you want to buy a salvage unit, do a Google search for places that sell salvage Prius parts; of course you will need the correct part number.

    However, given your post above, I am wondering whether you have the background to successfully remove and replace the ECU without causing damage to the car (or yourself).
     
  3. nuclear_j

    nuclear_j New Member

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    No that's not a problem. I'm a good direction follower. I can computers together from scratch. As long as it does not require extra special tools. I should be able to manage. Would you have any instructions on how to do this?

    I'm going to see if I can find what part number ECU I have.

    It looks looks like I have to remove the part to see the part number? Please confirm or correct. Thanks for your help.
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    When I sold my 2001 I also sold my repair manuals. If you would like to download the official Toyota repair docs, pls subscribe to techinfo.toyota.com

    To step back for a moment, I believe that you previously posted about engine start problems. The relevant DTC should be P3191/P3101. I am assuming that you have verified that the iridium spark plugs are in good condition, the spark igniters look OK (no cracks, burn marks, corrosion), the engine air filter is reasonably clean, the throttle body and throttle plate are clean, engine oil viscosity is 5W-30 and not overfilled, and you have sufficient gasoline in the fuel tank.

    If you have addressed all of the above and still have engine start problems, then it is time to replace the engine ECU if it is downlevel. You'll probably have to remove the current ECU to verify the part number.

    The latest revision is 89661-47054, and that is the one that you need to install. When you remove the current ECU, verify that the part number is 89661-470xy (where x is 3 or 5, and y is 0 or 1), so that you can confirm that you have removed the engine ECU and not some other ECU.

    In brief, the removal procedure would include the following:

    1. Make the car IG-OFF
    2. Disconnect the negative terminal of the 12V battery so that all ECUs can power down
    3. Gain access to the engine ECU by removing the glove box
    4. Carefully remove all engine ECU wiring harness connectors
    5. Remove hardware securing engine ECU to the dashboard frame
    6. Examine ECU part number and confirm this is the one that you need to replace
    7. Assuming that the engine ECU is downlevel (part number other than 89661-47054), order an ECU with part number 89661-47054
    8. Install new ECU, connect wiring harness connectors, attach negative 12V battery terminal connector, test-drive car in cold weather & see if you note any improvement.

    I'm interested to know what ECU part number is currently installed, after you have determined this. Good luck.
     
  5. nuclear_j

    nuclear_j New Member

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    Awesome! Thanks Patrick! I'll keep you updated!
     
  6. statultra

    statultra uber-Senior Member

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    make sure not to remove any other ECU, the HV ECU is also located in the same vicinity, and I believe it needs to be authenticiated with the transponder ECU and your vin number.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    On Classic, the hybrid vehicle ECU is actually located under the passenger-side (RH) carpeting below the dashboard.
     
  8. nuclear_j

    nuclear_j New Member

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    the ECU number currently installed is 89661-47031, I could see the number while still installed. We ordered a used one form ebay for $300 and pray that this will work!
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Thanks for the update; this part number shows that you currently have the second revision ECU installed; -47054 is the fifth revision. If this doesn't work, then you'll need to check fuel system pressure - but I think that is a relatively low probability issue.
     
  10. bobofky

    bobofky Member

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    The air filter you saw is the "Cabin Filter" and filters the air that enters the inside of the car. The service schedule calls for its replacemnt occasionally. The ECU is located under the floor of the passenger side of the car where the floor slants up to the firewall. The ECU is not hard to get to. Remove the plastic kick panel. Pull back the carpet and you will see a metal panel with about four screws. Remove the panel and you will see the ECU.
     
  11. nuclear_j

    nuclear_j New Member

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    Thanks for that. I really do hope this works.

    I just took out the old ECU by disconnecting the connections (both the engine and power steering) and then removing two bolts. One at the top and one at the bottom. The engine ECU and the power steering ECU are attached to a holding bracket that once you remove the bolts both will slide out.

    I took it out, removed the old engine ECU by removing 4 screws, and screwed the new one to the bracket. Putting it back in was not too tough; make sure you don't get any of the wires stuck behind the holding bracket and another thing to keep in mind is the two bolts should go back from where they came. Do not switch them.

    After bolting the bracket back in, reconnect the wires. I took pictures with my cell phone to remind me what goes where, but I did not need that as the connections are specific. Meaning, there is only one place for each of the connectors to connect to.

    Now I just need to give some juice (the battery is pretty dead from sitting for so long) to the car to start it and we will see if it is fixed!
     
  12. nuclear_j

    nuclear_j New Member

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    It Worked! Our car is showing no signs of the christmas tree! I cannot thank this board enough, especially Patrick Wong. Thanks dude! We went form a $2000 fix at the shop to a $500 learning experience. :rockon: Thanks again everyone!
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This was not an easy project to complete correctly; congratulations on your success!

    I note that one msg mentions a price of $300 while the other says $500. Does the $500 figure include other parts besides the engine ECU?
     
  14. patsparks

    patsparks An Aussie perspective

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  15. nuclear_j

    nuclear_j New Member

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    Yeah, I got an OBD II reader ($80) and also some spark plugs ($40) so actually around $420. But the part was $300. Thanks so much!