A/C Compressor question

Discussion in 'Prius c Technical Discussion' started by CMJAnew, Sep 4, 2025 at 6:24 AM.

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  1. CMJAnew

    CMJAnew Member

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    I’ve searched, but can’t find a “C” specific thread or tutorial on replacing the A/C compressor. I have a wicked noice coming from under the hood when A/C is on. Goes away when off.
    I’m not apposed to taking it to a garage (not my local Toyota dealer) but wouldn’t mind tackling a “simple” job.
    Thanks
     
    #1 CMJAnew, Sep 4, 2025 at 6:24 AM
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Failure rate is pretty low + they didn't sell that many in America = very little free DIY info in public.

    Probably the best thing you could do is rent the official Repair Manual from Toyota. It's not expensive and it is the best step-by-step info anyone ever wrote for the job.

    Details on this link.
     
    #2 Leadfoot J. McCoalroller, Sep 4, 2025 at 9:24 AM
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  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Also, figure out why the old one died. The two most common ways seem to be hitting road debris that hits the compressor itself, since it's pretty low on the front of the engine, and the other is loss of refrigerant.

    Because the car has automatic climate control, it will try to compensate for low refrigerant level by working the compressor extra hard, without telling you anything is wrong. Eventually it just does too much and thrashes itself to death.

    So... you may have more than just a compressor to deal with. Be suspicious and careful when you are leak-testing.
     
    #3 Leadfoot J. McCoalroller, Sep 4, 2025 at 6:12 PM
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  4. CMJAnew

    CMJAnew Member

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    I’m leaning toward the hitting debris scenario. Just had the HV coolant system repaired for ‘likely’ the same reason. For now, I’m thinking I’ll just disconnect the a/c and worry ‘bout it next spring.
    Thanks
     
    #4 CMJAnew, Sep 5, 2025 at 4:48 AM
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Sure thing! also, you should be aware of car-part.com. It's a database of parts in junkyards. Not the easiest-to-use website, but it is worth it because of the savings.

    With such a low failure rate, it means there's lots of perfectly good compressors available from crashed cars. You can save a bundle that way.

    Good luck!
     
    #5 Leadfoot J. McCoalroller, Sep 5, 2025 at 8:15 AM
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  6. Georgina Rudkus

    Georgina Rudkus Senior Member

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    A corroded low voltage control connector is the most common way that Prius AC compressors fail other than mechanical issues. Improper control signals could also lead to mechanical failure.

    The connector is so situated that it collects water and corroded.

    I filled mine with dielectric silicone grease to prevent this many years ago.

    Corroded connectors can't be repaired. A new compressor is the only option.
     
    #6 Georgina Rudkus, Sep 5, 2025 at 8:31 AM
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  7. CMJAnew

    CMJAnew Member

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    Thinking out loud…..I may purchase a vacuum test kit to possibly see if freon loss caused the fail. If that’s the case, I’ll have to study how to find the leak(s). If I can figure that out, I’ll likely fix it, or have it fixed (most likely) in the spring.

    As an aside….this is the same car the dealership repaired the HV coolant system along with the unauthorized maintenance items (from my recent thread). It’s funny,…the service writer said, and I quote; “you have a new car Ha Ha”
    When my lady friend (before I got a chance to stop her) called about the A/C, the same service writer said, and I quote; “the car’s not worth fixing”

    Can’t make this crap up._____.It’s a 2012 with 130,000 miles and no rust.
     
    #7 CMJAnew, Sep 5, 2025 at 3:27 PM
    Last edited: Sep 5, 2025 at 3:33 PM
  8. ChapmanF

    ChapmanF Senior Member

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    If I remember right, an algorithm got added into late-ish model Prii where you can straight-up ask Techstream if the refrigerant charge is correct. The car already has a variable-speed compressor, a high-side pressure sensor, and evap and ambient temperature sensors, so it was just a matter of adding some ECU code to use those features to judge the refrigerant charge. Saves having to open the system for the more invasive ways of judging that.

    My 2010 hasn't got that feature, but something in the back of my mind thinks I might have been reading about a c when I first learned of it.
     
    #8 ChapmanF, Sep 5, 2025 at 3:46 PM
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