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A/C Compressor not staying on.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by xraydog, May 30, 2023.

  1. xraydog

    xraydog Junior Member

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    My Prius A/C compressor is running but it's cycling on and off every two seconds. It's acting like it wants to continue pulling a vacuum but then it stops just before the low side gets to where it should be. I am still getting cool air out of the vents, but it's not where it needs to be.

    I took it to a shop today and they told me they couldn't help any further. But they did pull a vacuum and added the "correct" amount of r134. unfortunately the problem persists. My radiator fans also do not seem to kick into high but im not sure if that's the cause. No other check engine light or DTC code.
     
    #1 xraydog, May 30, 2023
  2. JC91006

    JC91006 Senior Member

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    Did you go to a shop that works exclusively with hybrids? The refrigerant in the Prius usages a specific oil, which cannot be contaminated with other oils from other non hybrid cars.
     
    #2 JC91006, May 31, 2023
  3. Tombukt2

    Tombukt2 Senior Member

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    Sounds like there's a blockage somewhere apparently you only have a low side gauge so when you're looking at the gauge and the compressors running it pulls down to where and then they get low gauge starts rising again so what's it pulling down too 40 60 what have you tried unplugging the pressure switch for a minute just to see what happens sounds like there's a restriction in a line maybe on the high side maybe the high side is kicking way up to almost 300 or so tripping hi limit.. the fans are a good place to start.they or it needs be on . Could be trash in line .
     
    #3 Tombukt2, May 31, 2023
  4. Tombukt2

    Tombukt2 Senior Member

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    Did they say how low it was just a few ticks or half a can?
     
    #4 Tombukt2, May 31, 2023
  5. xraydog

    xraydog Junior Member

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    Hi everyone. Turns out it was my high side a/c sensor which went bad ant got stuck reading high. Which then caused a loop effect of the compressor turning on and then off repeatedly. I verified by bridging the connectors on the sensor plug, then everything worked normally.
     
    #5 xraydog, Jun 1, 2023
  6. Tombukt2

    Tombukt2 Senior Member

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    That'll do it
     
    #6 Tombukt2, Jun 1, 2023
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