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"Hybrid System" fuse missing

Discussion in 'Gen 2 Prius Technical Discussion' started by Kristen678, Aug 26, 2020.

  1. Kristen678

    Kristen678 Junior Member

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    While troubleshooting another problem, I learned that the 7.5 amp AM1 Hybrid System fuse is missing from the fuse box under the driver's dash. I bought it used and have been driving it this way for two years without any warning lights or indications something was amiss. I've been trying to get specific information on what this fuse actually does but I keep turning up zilch. I'm particularly curious about this because after I bought the car, I learned a shady dealership hobbled together a hybrid battery to replace the original and created a pretty dangerous situation. Luckily, and thankfully, I discovered the issue and replaced the battery but I'm thinking it may have been them that pulled the fuse. How can the car function without this fuse?
    Does anyone know?
    Thanks
     
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  2. bisco

    bisco cookie crumbler

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    techinfo.toyota.com
     
  3. davecook89t

    davecook89t Senior Member

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    Looking through the manual at all the references to AM1, about 1/3 of them are in the Smart Key System section. There are probably other systems whose wiring runs through this fuse, but just as a point of interest, does your car have a Smart Key and does it function like it should (i.e. can you open the door without removing your key from your pocket or purse and start the car without inserting the key in the key slot)?
     
  4. Elektroingenieur

    Elektroingenieur Senior Member

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    I’m not sure there is supposed to be a fuse called “AM1” on your car.

    The Owner’s Manual (PDF) shows it on page 430, as item 14 in the list, but the Electrical Wiring Diagram for 2006 Prius cars (EM01R0U, more info) doesn’t: the illustration of the Driver Side J/B (junction block) shows no fuse in that position, and neither the System Circuit nor the Power Source sections mentions any fuse called “AM1.”

    For model year 2004, there were fuses called AM1 and AM2, feeding the AM1 and AM2 power supply inputs of the Power Source Control ECU, respectively. For model years 2005 and later, however, it seems that Toyota eliminated the AM1 fuse, leaving the AM1 and AM2 inputs both fed from the AM2 fuse. It’s likely that when this design change was made, the junction block and its label weren’t modified, probably to avoid the costs of creating and stocking another version of those parts.

    The ECU monitors these inputs, by the way, and if one were faulty, diagnostic trouble code B2271 would be stored.
     
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  5. Kristen678

    Kristen678 Junior Member

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    It looks like Electroingenieur puzzled it out but I really appreciate you checking your manual. It was very kind of you!
     
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  6. Kristen678

    Kristen678 Junior Member

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    Wow - that is some serious detective work! I'm seriously impressed and very grateful to have the answer. Thank you!
     
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  7. edthefox5

    edthefox5 Senior Member

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    Yes that's correct my 07 manual shows where AM2 feeds 2 inputs of the Power Src IC.

    Pin12 is marked AM2 and Pin 33 is marked AM1. Both fed by good old AM2 fuse. So disregard empty AM1 fuse socket.

    Good eye Kristen you will need that down the road on this car lol........and both you AND Electro gets a
    I Like YOU!
     
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