Weak Gen2 Air Conditioner mystery puzzle; dealer can't fix

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by squeezix, Jun 17, 2011.

  1. squeezix

    squeezix Junior Member

    Joined:
    May 24, 2007
    4
    4
    0
    The A/C on my 2006 has been weak for more than a year. I've had it to four shops so far (including 2 dealers), three of the four agreed that there was definitely a problem, everybody agreed that coolant pressure, coolant purity, compressor, electronics, etc etc, were all excellent, and nobody (including the dealer!) had any ideas on how to make the dang thing work.

    So I'm turning to the wisdom of the forum.

    Whaddaya do when the blowers, interior fan, exterior fan (including that loose blade problem), compressors, etc, are all fine, but the A/C normally just blows "cool-ish". I.e., five degrees colder than ambient if the car is sitting in the shade, and "hopeless" if in the sun.

    (Except sometimes, of course. That one dealer that said there was no problem had it just sit and idle on "LO" in the back of the shop, in the shade, and reported that after a couple hours the interior had gotten down to 23 degrees colder than ambient. Couldn't get them to do a road-test; they were busy.)

    One hint: the compressor runs at full speed all the time.

    Are there any obscure plugged filters that might have been missed?

    thanks for any insights.

    Garry

    PS - Air flow in the cabin interior is excellent, but I'm wondering if things might nonetheless be plugged. Anyone know where the interior part of the plumbing lives / how to get to it? I'm not positive that that's been eyeballed.
     
  2. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,489
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    The compressor is usually the problem with A/C. So if that is not the problem here, then you need to find a tech that will dig in. Potential sources of error are the A/C amplifier and the air mix servo/damper. These are deep in the bowels of the dash -- that interior part of the plumbing. If you post your town and state, perhaps one of us could suggest a shop.
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,165
    6,227
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    1. What evidence do you have that the compressor is fine?

    Feel the low pressure side of the AC compressor plumbing after the compressor has run for a while. It should be very cold and you may see water condensation on the piping. The high pressure side will be quite hot.

    If the compressor is really running at full speed and you do not observe this, then I would question the assertion that the compressor is working properly.

    2. Is it possible that insufficient, or excessive refrigerant is in the system? Has the pressure on the low and high sides of the system been checked?

    3. Why not go back to the Toyota dealer who agreed that the system has a problem and ask them to consult Toyota tech support for assistance.
     
  4. squeezix

    squeezix Junior Member

    Joined:
    May 24, 2007
    4
    4
    0
    Pardon the time lapse. Forgot to subscribe to the thread.

    The evidence for the compressor being fine is that two of the shops - including the shop with the real-good reputation and the $200 charge for taking a look at all these things - explicitly told me so. Likewise for the coolant (one of them found a small amount of air mixed in, but not enough to matter.)

    "Consult Toyota tech support"? There is such a layer beyond the local dealerships? Cool. The 1st dealer was really apologetic they couldn't figure it out; I'd'a thought they would have called on the extra resources automatically if they had them.

    Hurrah! You're using new-and-different words! I like it. As far as I know nobody's been inside the dash at all. I started taking the dash apart myself last week, but I didn't know exactly what to look for. Or how to do it.

    I'm near Berkeley, California. The "real-good reputation" shop was Art's Automotive. The dealers were Hilltop and Downtown-Berkeley. Downtown Oakland's also been into it, but primarily for a regular radiator problem. (I'd rather not go back to the Oakland or Berkeley dealerships; their general service quality hasn't been very good over the years.)
     
  5. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,656
    998
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
  6. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,489
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    Wow, Art's has one of the best hybrid reputations in North America. They have even written articles on hybrid A/C service by independents. Definitely give Luscious a try, they are well known for fixing tough problems.
     
  7. squeezix

    squeezix Junior Member

    Joined:
    May 24, 2007
    4
    4
    0
    The actual status with Art's is that he wanted to try something expensive but didn't have a lot of confidence that it would work. Meanwhile, a guy up in Marin was confident he had The Answer. So, retrieved the car, called the shop in Marin back for an appmt, and they denied all knowledge of anything... oops.

    I will dig for the notes on what Art's said.

    SF/Luscious: awful far! About 1.5 hours to drop off or pick up via bus/bike/Bart, if Nothing Goes Wrong....
     
  8. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,489
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    I would like to see what Art's had to say. Unfortunately, you may be at the point where the dash needs to be disassembled to do further troubleshooting. The A/C amplifier is not cheap either ($475).
     
  9. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,656
    998
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
    An hour and a half versus dinkin' around with it for another year. Your call :_>
     
  10. imwoody36

    imwoody36 the prius parts guy

    Joined:
    Sep 29, 2005
    143
    111
    0
    Location:
    southern Indiana
    Vehicle:
    2008 Prius
    I will troubleshoot it for 90 dollars over the phone.
    if I cannot diagnose it , i'll give ur money back.
     
  11. kammssss

    kammssss Member

    Joined:
    Mar 30, 2007
    287
    84
    0
    Location:
    SoCal
    Vehicle:
    2005 Prius
    Model:
    Two
    Here is a theory: Inverter Coolant Pump

    Today I got the triangle of death on the dash, which is the Hybrid warning sign. I just left the dealer right now with it being replaced via recall. This is what happens when the inverter pump is dead: AC will blow warm even when you put it on 65F. I don't know the exact relationship with the inverter pump and AC. They must work together somehow because the AC is now FREAKING COLD. I live in Los Angeles and it was 102F on the drive back home. AC was set on 78 and on the second setting. I know the stealership didn't give a complimentary AC charge. Also, I noticed that the AC was blowing on the weak side a few weeks ago. Maybe the inverter pump was not running at optimum level and consequently lowering the AC temperature. My car is an 05 with 186k. I hope that gives you some clue.
    Good luck.
     
    briazen likes this.
  12. spitinuri

    spitinuri Member

    Joined:
    May 23, 2008
    317
    13
    0
    Vehicle:
    2004 Prius
    The same thing happened to me last week. It would not trigger a code until it actually failed. Mine was 188K miles when it failed, though I have heard some failing much earlier.
     
  13. jdoom38

    jdoom38 New Member

    Joined:
    Apr 4, 2010
    6
    0
    0
    Location:
    texas
    Vehicle:
    2006 Prius
    Model:
    V
    i have a 2006 with 34K miles and am having similar issues. I live in Texas so it gets insanely hot here, but the a/c should work even in extreme heat.
    my a/c blows cold then it would warm up a bit (to the point where i am not comfortable and start to sweat) then a few minutes later would cool a bit and then the process continues.

    i took the car to my dealer and they found nothing wrong with it and said to return it when the issue was occurring.
    i did exactly that and again they could not find anything wrong with it, even though they did a complete a/c diagnostic for free. their tests said it was blowing 40F and all systems were ok. on the way home from this testing the problem continued.

    i took it a 3rd time and now they said a relay switch is faulty. He said the relay is tripping when the compressor gets too hot. He said they need to replace the compressor and another part (I forget the name) and to give them $2,300 to do so. Something doesn't sound right to me. If the relay tripped the unit wouldn't blow ANY cold air, correct? Do they want to replace the entire system because they cannot actually locate the issue?

    I live near The Woodlands, TX (north of Houston) if that helps identify qualified mechanics.

    Any suggestions? I greatly appreciate any assistance.
     
  14. seilerts

    seilerts Battery Curmudgeon

    Joined:
    Mar 7, 2010
    3,326
    1,489
    38
    Location:
    Santa Fe, NM
    Vehicle:
    2005 Prius
    You might have a leak which has caused moisture to enter the system. That moisture will freeze and block the flow of refrigerant. The cold/warm cycle corresponds to the freezing/thawing of that moisture. Try calling around to A/C shops and see if any of them have the right equipment. High voltage compressors take special oil (ND-11 or equivalent), so if you find a shop that is aware of this, you are at the right place.
     
    1 person likes this.
  15. jdoom38

    jdoom38 New Member

    Joined:
    Apr 4, 2010
    6
    0
    0
    Location:
    texas
    Vehicle:
    2006 Prius
    Model:
    V
    Thanks for the words of advice.
    If you have a leak wouldn't the refrigerant be blown out under the pressure of the system and the unit would blow hot and quick burn out the compressor?
     
  16. koolingit

    koolingit Member

    Joined:
    Mar 17, 2009
    158
    49
    0
    Location:
    Mocksville NC, USA
    Vehicle:
    2009 Prius
    Moisture usually gets into the system when parts are replaced or when you drive around with no charge in the system for a long period of time or when the wrong person hooks up gauges to the system.

    If moisture is your problem, you will have to recover the charge, replace the dryer, evacuate and recharge the system. The dryer is just a bag of desicant. Its job is to trap any last little bit of moisture that a good evacuation didn't get rid of. Liquid refrigerant flows through it all the time and it constantly scrubs out all moisture and everything works fine.

    But .... when there's more moisture than the dryer can handle, the dryer can't hold all the moisture and the expansion valve starts to ice up. A dryer might work fine in 80 or 90 degree weather but when the temps get over a 100, the dryer's ability to hold moisture decreases and it will start to give up moisture. So you take your car to the shop and they check it in the shade with cross ventilation and all is fine. When you get back in the sun the trouble starts again.
     
  17. jdoom38

    jdoom38 New Member

    Joined:
    Apr 4, 2010
    6
    0
    0
    Location:
    texas
    Vehicle:
    2006 Prius
    Model:
    V
    yeah, that is what seems to be happening. worse in the hot sun. when 80-90 degrees it seems to work ok
    I will print this out and give to dealer to be sure to check it.
    thank you!!!!
     
  18. jdoom38

    jdoom38 New Member

    Joined:
    Apr 4, 2010
    6
    0
    0
    Location:
    texas
    Vehicle:
    2006 Prius
    Model:
    V
    I took it to another dealer and he said they have to replace the condenser and compressor. they said the compressor seized and must be replaced. nothing else to do.
    great forum!

    next i want to know how i can customize my LCD. I am tired of the "info" screen and want "audio" to be the default
     
  19. koolingit

    koolingit Member

    Joined:
    Mar 17, 2009
    158
    49
    0
    Location:
    Mocksville NC, USA
    Vehicle:
    2009 Prius
    This dealer that said the compressor seized is either using that term very loosely or he's full of soup! If your compressor has seized, you're getting no air conditioning. If you're getting some air conditioning, then the compressor has not seized.

    There is something else you can do: find, yet, another shop!
     
  20. Kablooie

    Kablooie Member

    Joined:
    Feb 21, 2004
    273
    11
    0
    Location:
    La Canada
    Vehicle:
    2016 Prius
    Model:
    Three
    Did anyone ever figure out what the solution was?
    I've got the same air conditioner problem on a gen 2 2004 Prius.
    I've asked Longo Toyota to look at it a couple of times but they always say everything is fine.

    A few years ago I ran over a curb and damaged parts of the air conditioner which are positioned low in the front of the engine.
    Longo replaced it but the temperature problem didn't occur immediately but a year or two later so I don't know if it is related.
     
Loading...