hybrid vehicle ECU location?

Discussion in 'Generation 1 Prius Discussion' started by VacantStance, Apr 4, 2020.

  1. VacantStance

    VacantStance Junior Member

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    Is there a reason why I can't seem to find an image of a gen 1 hybrid vehicle ECU actually in the vehicle? I have read a couple of places that it is under the carpet on the passenger side of the vehicle. Why hasn't anyone shared a photo or diagram? Why is this image so elusive?
     
  2. Trombone

    Trombone New Member

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    It's behind the glove box. I'll post a link in my next reply; as a "new member," I have to have posted four times before I can post a reply containing a link.
     
  3. ChapmanF

    ChapmanF Senior Member

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    My Gen 1 manual is in dead-tree format so I can't just paste an image, but you can also view it online (more info).

    Anyway, if you're wondering, it's under the carpet where the passenger's feet go. Why are you looking? Haven't heard they act up much. Car get flooded?
     
  4. VacantStance

    VacantStance Junior Member

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    I bought this car for the parts, so I didn't hear it run. The Seller attempted to start it, but couldn't. I bought it anyway because of the parts. It had a strong mildew smell in the carpet. I assumed it got rain in it. My codes keep giving me C1259, P3106 & P3030, all related to the hybrid ecu and vehicle ecm, so I swapped the ecm from my 2002 and no change. I’ve inspected the wires, so the next thing to check is the hv ecu. I figured it out, so I swapped the one from my 2002 and still no joy. I’m doing the whole “jumper from #4 to #13 with the ignition in the ON position in order to reset the anti theft “ thing. If this doesn’t work, I’m done. The testing the wires for certain voltage or current is beyond my ability so I guess the next step is to have it towed to a Mechanic and write a check.
     
  5. ChapmanF

    ChapmanF Senior Member

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    That's not a thing at all as far as I know. Will make some lights blink though.

    There is a procedure in the manual for introducing a new HV ECU to the existing immobilizer ECU, should you end up needing to do that. Takes about half an hour. Probably good to have a charger supporting the 12 volt battery so it doesn't go flat mid-procedure.
     
  6. VacantStance

    VacantStance Junior Member

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    I didn't describe it right, but that's the procedure I used. It didn't work. I'm not sure what's wrong. I'm researching local hybrid mechanics so I can have it towed and properly looked at.
     
  7. VacantStance

    VacantStance Junior Member

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    I tracked my issue to the 15a EFI fuse blowing while starting. I replaced the fuse with a 12 volt bulb and tracked the problem to the ECM. When I unplugged the bottom cable, the light went off. I then swapped out the original ECM for the one out of the donor car, thinking that if the light goes out, my problem is solved, or at least if the light is illuminated and I unplug the bottom cable, my issue is in the wire loom. I installed the other ECM and the light returned. So I unplugged the bottom cable, but surprisingly, the light stayed on. I then unplugged the next one up and then the third and the light went out when the third cable from the bottom was unplugged. So I have two bad ECMs.

    I'm pissed because I had an experience awhile back where I sent my donor car ECM to be repaired somewhere in Florida through Ebay for a cool $80. My ECM was kept for quite some time and then I got a call from the "shop" saying that they couldn't confirm that my ECM was damaged, but they could sell me a refurbished one for $400. Of course, I refused and when they returned my ECM, it was not mine and it was riddled with problems. They even kept my $80 because the transaction had lasted outside of the allotted time Ebay allows you to dispute. My donor car at the time was my daily driver and it never ran the same again. I know better now. Onward, upward.
     
  8. Nelsonprius

    Nelsonprius Junior Member

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    I hope you could still rate the seller and/or make a Yelp review
     
  9. VacantStance

    VacantStance Junior Member

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    Neither.
    Their Ebay name was not there brick and mortar name and Ebay didn't give me access to offer feedback.
     
  10. VacantStance

    VacantStance Junior Member

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    No joy. New (to me) ECM. 15a EFI fuse still blowing.

    I thought I was on track when I stumbled upon this post. Any suggestions?
     
  11. ChapmanF

    ChapmanF Senior Member

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    Looks like a good find. Are you going to take a multimeter and start checking out the possibilities TMR-JWAP laid out in post 31 of that thread?
     
  12. VacantStance

    VacantStance Junior Member

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    Lol, I hadn't gotten that far in the thread. I just read it and yes, I'll check everything he references in that post.

    Edthefox5 was so confident in post #9 that I decided against investigating the oxygen sensors. It just so happens that when I bought the car, it was missing the catalytic converter. There may be a clue under the car.
    I plan to tackle the oxygen sensors, and everything else he mentioned, in the morning...the bugs are feasting on me.
     
  13. VacantStance

    VacantStance Junior Member

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    IMG_2786.JPG IMG_2787.JPG IMG_2788.JPG

    So I went back to post #31 of that very helpful thread and the 1st thing on the list I decided to check out was the oxygen sensor connection under the carpet on the passenger side...Problem solved. The sensor cable lead to nowhere.

    Now that the short is solved, should the car at least turn over with the oxygen sensor missing/unplugged? Mine doesn't. I pulled two trouble codes: 3106 & 3030. The 3030 code I'm all over. It's that darn harness that I took weeks to clean and remove corruption from. I used the copper paste to slow any future corruption...but there was a single sensor wire that I broke and I replaced with a ring terminal... which was probably not good enough. Back to the bench.
     
    #13 VacantStance, May 23, 2020
    Last edited: May 23, 2020
  14. ChapmanF

    ChapmanF Senior Member

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    Please don't leave off the letter at the front of a DTC. It means stuff.
     
  15. VacantStance

    VacantStance Junior Member

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    Sorry.....P0306 & P3030
     
  16. ChapmanF

    ChapmanF Senior Member

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    Just noticed your .sig. I'm going to have to remember that!

    You didn't mean P0306, though, did you? I'm not sure that's actually a thing.

    It could be a misfire, though, if you somehow scored one of the rare 6 cylinder Prius sedans.
     
  17. VacantStance

    VacantStance Junior Member

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    Sorry again! P3106, not P0306. I must have been tired...jeez.
     
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