A/C Diagnosis Help

Discussion in 'Gen 3 Prius Technical Discussion' started by kripley1, Jun 21, 2021.

  1. kripley1

    kripley1 New Member

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    Hi folks,

    Im in need of some help figuring out what’s really going on with the A/C in my 2010 Prius.

    Symptom:
    -When I turn on the A/C it blows warm air. No change between auto mode and manual temp/fan control.
    -Occurred about a week ago and happened all at once (A/C was blowing ice cold the day prior, then warm the next day.

    I pulled the codes and did the A/C Diag mode. I’m getting a B1423 and a 23 code on the console. Both of these refer to the pressure switch.

    I brought the car to my normal mechanic (not a Toyota / Prius specialist - this seems like a mistake). He diagnosed it as a bad compressor, evidently he put a 20a fuse where the 15 should be under the dash and that allowed it to run - this makes no sense to me given that this is an electric compressor and not belt driven, and that it runs on the high voltage system. Anyway he quoted me $1900 for a compressor replacement which I’m not ready to spend. He also recovered and recharged the refrigerant.

    After I got it back I’m still getting the same codes.

    If my logic is correct and if I trust that he recharged the system properly, then the pressure switch code should actually indicate an issue elsewhere since we know the pressure and volume are ok.

    Can anyone point me to any checks for the pressure switch itself and or the wiring for it?

    If the pressure switch is bad what is involved in the replacement? Is there a schrader valve or similar under it? Or will I need to get the system recovered and recharged?

    Any help is greatly appreciated.
     
  2. burebista

    burebista Member

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    If the guy is not a Prius mechanic ask him what oil put in your AC because Prius need ND11 oil.
     
  3. Georgina Rudkus

    Georgina Rudkus Senior Member

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    The pressure switch means that there is a low refrigerant charge and a leak somewhere. Low refrigerant will activate the pressure switch to shut down the compressor.

    The only way is to repair this is to fix the leak, evacuate the system and to refill it with the factory specified charge.

    Just adding refrigerant from a can with anything other than pure R-134a and ND11 oil might destroy the system.
     
  4. ChapmanF

    ChapmanF Senior Member

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    Well, for starters, you don't have a pressure switch but a pressure transducer, and it's a bit pricey.

    A pressure "switch" would tell the A/C computer whether the pressure is anything above x but not higher than y. The pressure transducer tells the A/C computer what the actual pressure is. You can watch it in real time in Techstream. (Sometimes that's handy in diagnosis; it's like not having to bother hooking up the high side of your manifold gauge, because you can read that pressure already.)

    There's also not a Schrader under it; the refrigerant would have to be recovered first, then recharged after.

    I'm not sure how often the pressure transducer really goes bad. There's a risk of shooting the messenger, if what it's telling you about the pressure just happens to be true, and the reason is somewhere else.
     
  5. Tombukt2

    Tombukt2 Junior Member

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    i do a bit of ac work i run a not stock gas in my persona 13 system.. itll blow snow out vents. no shiet.. ive not looked at tecstreams pressure info . but 134 A is going to adhere to pressure stds for that density gas.. doh..im still lookin that near 40 on low side.. that should produce a very cold low side tube... fat one.. same gas in my 09 1 NZ car.. I do not know if this units an inverter type system.. not sure why id be interested in hi side pressures. unless theyres a blockage . this would wreak havoc on system fo sho.. wen system at rest theyre is no hi and lo sides ...so air or gas should be able to move thru out system un restricted. whilst comp. is off.. this is a troubleshooting clue. Are you saying higher amp fuse is starting compressor and making cold .. /////????????
     
  6. lech auto air conditionin

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    other than you have to look up the exact instructions for your 2010 Prius.

    only perform this procedure if you’re 100% sure you still have refrigerant in your system otherwise you will damage the compressor.

    Locate and download the instructions for your 2010 Prius on how to test the pin connectors of your pressure switch on your 2010

    I guess I need to make videos for every model generation Prius pressure switch and put in my media album on PriusChat for reference
     
    Georgina Rudkus likes this.
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