B1476 AC Compressor Not Working - seeking sage advice

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Chicago David, Jul 5, 2026 at 10:40 PM.

  1. Chicago David

    Chicago David Junior Member

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    Hola All! Our trusty 2005 Gen2 is blowing hot air w/ AC set to Max Cold - read all of the other posts, looking for a few additional opinions
    • Fuses and relays are good
    • Cleaned the pressure valve connections
    • Condenser fan spins when AC turns on, runs for a few seconds and stops
    • Originally thought the compressor wouldn’t kick on due to low 134a, low side was about 55 psi with the compressor not working which calculates out to a little low
    • Added some 134a and the low-side pressure is around 85 psi which seems right with the compressor not kicking on and the ambient temperatiure
    Both B1476 history and live DTCs are showing along w/ the B1421 (but it was very cloudy out today and I could clear the code sometimes).

    Is it time to buy an OEM compressor or is there anything else I should check or do?

    Thanks Community!
     
  2. Tombukt2

    Tombukt2 Senior Member

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    So what's the problem when you put the air condition on LO not a temp . And hi fan . If you get out and touch the big fat silver hose and it's coooold. You're . Making the cycle . Because it's not making it into the car is another situation . So we're we at here?
     
  3. ChapmanF

    ChapmanF Senior Member

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    The repair manual section for B1476 pretty much tells it like it is. The electrical power drawn by the compressor in operation is being measured too low or too high for the conditions. It can be too low if there's not enough refrigerant. It can be too high if there's too much refrigerant, or if the compressor is failing and hard to turn.

    It's up to the human to figure out which of those possibilities it is, then fix.
     
    BiomedO1 likes this.
  4. Chicago David

    Chicago David Junior Member

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    Thanks - tried running it not on “auto” with fan on HIGH but the temp higher (72 degrees instead of MAX COLD). The silver hose is not cold on either side of the valve and still not hearing the compressor doing its thing.

    Could not tell if the radiator fans were spinning up this time though because I was by myself.

    Thoughts?
     
  5. Tombukt2

    Tombukt2 Senior Member

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    No temp we want lo we want the compressor running wide open not some number that you decide you want to set because it's above something you think we're trying to get past you're thinking.. so if you don't hear the compressor doing its thing set like I'm talking about then more than likely you don't have enough gas in the system for the system to recognize and turn on the compressor for simple enough. Most AC systems are built this way your house your car window unit etc . No gas present means nothing is going to run it's a safety feature
     
  6. BiomedO1

    BiomedO1 Senior Member

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    You shouldn't just randomly fire freon into a variable speed compressor setup. The system needs to be evacuated and the correct amount of freon needs to be injected into the system (by weight, NOT by pressure). You can't just go by pressure readings, without doing a bunch of calculations, which would include the current rotational speed/displacement of the compressor.
    The error code is telling you that the compressor can't turn so:
    1. you've got a defective compressor.
    2. it's not getting enough power.
    3. freon pressure is too high or low and the safeties are cutting in.

    You need to test to see what your actual problem is and rectify it - or you can just keep groping around in the dark, firing the parts cannon at it and hope you get lucky.

    YMMV
     
    #6 BiomedO1, Jul 11, 2026 at 11:52 AM
    Last edited: Jul 11, 2026 at 12:47 PM
  7. ChapmanF

    ChapmanF Senior Member

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    Well, the code is telling you that the electrical power drawn by the compressor in operation is being measured too low or too high for the conditions. It can be too low if there's not enough refrigerant. It can be too high if there's too much refrigerant, or if the compressor is failing and hard to turn.

    It's up to the human to figure out which of those possibilities it is, then fix.