Intermittent AC Problem 2004 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by LEARNER, Jan 5, 2020.

  1. LEARNER

    LEARNER Junior Member

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    Detailed history of problem as best I can describe. Feel free to ask questions or clear up any misunderstandings. Thanks very much in advance for any help. I need AC to be working as I drive all over the country on work contracts camping in Car and sometimes need AC some in Southeast.

    Prius has over 200K miles and thousands of hours idle time used as office during days. Evaporator core I believe and some other parts were replaced years ago.

    History early 2018
    Original AC Compressor failed and was replaced
    Traveled to Eureka CA and worked there a year not using AC or car much just to go to work close by.

    Returned to Wilmington NC and later in August AC Compressor stops working.

    Took to a shop that later learned had no business working on Prius AC where there were multiple revisits same day (and later) with warning lights going off then finally they got it working claiming they had to reset computer, computer relearning, 24 diagnostic with no printout (all questionable)

    A month or so later AC stops working intermittently and they same shop replaces warrantied AC Compressor ...same story multiple revists on and on.
    Owner uses his tablet auto computer to try and diagnose. It has a crack accross the screen. I believe that computer or something created some temprary electrical anomalies in car (volume knob on stereo stopped working, locking side front door made a loud buzzing sound and forgot what else but gone now)

    Finally desparate for specialist took to Toyota Dealership thinking they were the experts.

    1st visit they claim freon low and they topped off, dye check...no leaks

    Had to return that day because intermittent ac failure and some grinding sounds randomly for seconds (I believe from the compressor - sounded like sometimes could have been trying to engage??)

    They rechecked and find wire loose to new dual fan last shop installed and then condensor cooling fan started worked and everything was fine

    Week later noticed moving temp setting up and down sometimes randomly associated with intermittent AC failure (not blowing cold air)

    Toyota relooks at it and claims that freon needed topping off and another dye check revealed no leaks and air mix server door was the cause and said that would fix the problem for $850 so I agree.

    After repair at first it was working but keep testing it to be sure moving temp up and down changing where ac blows, driving, not driving, leaving running for extended time (although outside temps are decreasing).

    So finally after some time after leaving running for a while parked and then back to driving all of a sudden ac starts blowing warm not cold air.

    Also noticing long delays 30 seconds or more to engage AC compressor plus have to turn temp many times to max cool to get the AC Compressor to engage with outside ambient air temp in mid 70's.

    Immediately take to Toyota for them to witness the condition and check out which the manager agreed to before.

    Again they say they topped of Freon and dye check revealed no leaks and I'm not seeing any leaking on driveway or smelling anything.

    Manager says bring it back in a couple months, claims it may be an internal leak.

    Then had falling out after visit number 4 and no solution from their Hybrid AC Tech and they refused to refund repair that had no effect and did not give the old part back as requested.

    The tech claims that the servo door that control the cold air mix was making the grinding sound which I believe is wrong.

    Everything starting to sound questionable claiming freon low each time, grinding sound still happens randomly (although not presently)

    Weather gets real cold and decide to put on hold until I find trustworthy knowledgable shop on Prius AC system.

    Lately AC works fine if you leave on coldest setting for a good time but if move the temp around or just up rather than max cool setting and let it run for a while and then drive it may stop blowing cold air

    BUT As soon as you turn car off and immediately back on it will work fine blowing cold air, sometimes you have to wait a minute or two before restarting car.

    I've not heard the grinding sound in a long while.

    I talk to a knowledgable owner mechanic about it but haven't gone to him yet and he thinks it may be electrical or what ever controls the servo door maybe

    I wonder if AC system was ever really low on freon as it blows extremely cold air when working or when turning car off then on.

    I don't think Toyota followed all troubleshooting steps

    I had to search for for the 2 ac self diagnostic codes still present after every visit with them.

    My gut and several communications with them and then remembering long past dealings with them leads to distrust in anything they said plus they found out I was talking with their sales staff looking at newer Priuses.

    I noticed one thing when the ac stops blowing cold air and have it set to blow air directly at me through the vents you can hear the air blowing or the AC blower blowing somewhere but barely through the vents so I check the defroster vent and floor vents but no air flow.

    Like it is blowing somewhere but not blowing through any of 3 outlets (defroster, floor, mid-level vents).

    This has happened before years ago randomly and I would tun car off for a while and back on and it would resume blowing cold air that you could feel blowing strongly on the mid-level vents in the high speed setting.

    Note though that in the first ac failures with the previous shop and Toyota it would blow warm air with the same force

    In the summer months in coastal Carolinas it gets very hot and high humidity and thought it may have been the automatic cutoff switch to protect the AC Compressor.

    Although this cutoff switch would usually only happen on a very hot day where you would leave car parked not in the shade and car on Max cool a situation I usually avoid instead parking in the shade with the temp set to 76 degree F Max fan speed while I run in store with my dog in car.

    At present I don't trust AC system to do that anymore and haven't had to because the lower temps.

    The new AC Compressor is not OEM. It is Oreilly's Brand Import Direct. Toyota said there was no problem with the AC Compressor.

    Kicking myself for not having Toyota replace the AC Compressor with their OEM AC Compressor because found out they would have charge $350 less than the shop that didn't know what they were doing. At this point I'd be willing to do that if that is what the problem is.

    Still would be cheaper than getting even a newer old Prius and I changed the Hybrid battery 3 years ago.

    Still get about 45 mpg on the Interstate and up to 52 mpg in the city.

    I'm in the car a lot so I listen too and study every peculiar sound the car makes such as hearing the dual fan go on and off with ac continously which it didn't do before and no one could find any problem with it but long story short it was running loudly is all plus the condensor fan was not running.
    With a new dual fan properly connected everything is quiet again but wonder if condensor fan was not running for an extended time if that could have stressed the AC Compressor or system.

    Not absolutely sure it wasn't running and how long though, just when I checked. Don't know if it runs continously while AC is on and car is parked idling.

    Current Update 1-5-20:
    You can leave the AC running on max cool a long time. Use to be able to do that as long as you didn't move the temp up and just leave on max cool.

    Lately notice after an extended time it will stop blowing cold air and have to leave car off longer 3-5 minutes and turn back on and it will work again blowing cold air.

    Before as I said If it stopped blowing cold air you could just turn car off and then immediately back on and it would start blowing cold air again. Thanks again for any input :).
     
  2. SFO

    SFO Senior Member

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    Bit of a long read, but time to ping @lech auto air conditionin for any input or help.

    @LEARNER - Maybe you can set up an appointment the next time you're on the west coast.
     
    Raytheeagle likes this.
  3. LEARNER

    LEARNER Junior Member

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    Thanks for reading and the info. Where are you?

    Forgot to add AC self diagnostic code 76. Use to have I believe 43 but it dissapeared and I know 21 is for solar sensor.
     
    #3 LEARNER, Jan 5, 2020
    Last edited by a moderator: Jan 5, 2020
  4. SFO

    SFO Senior Member

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    Northern California, which is where @lech auto air conditionin works out of.

    Send a PM before you come back to the best coast and see what they can work out.

    You might look into procuring a mini-vci cable and techstream, which may help with further diagnostics.
     
    Raytheeagle likes this.
  5. lech auto air conditionin

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    After reading all that I just want to close the email run away to another state and bury my head underneath the sand.

    1: sounds like you had more than one problem and to get things off to a start a compressor failure is usually a result of another component or low on refrigerant causing the compressor failure. The compressor failure is just a symptom of another problem.

    2: then it sounds like compressor failures and other problems some started and caused by the individuals trying to look for or fix other problems.

    3: now let’s tackle this by dividing up the problems into categories. The mechanics of the air conditioning system versus the / electronics and controls.

    4: let’s tackle the easy stuff first the mechanical physical components and moving parts of the air-conditioning system if this is 100% good and everything done correctly then there is no guessing about the diagnosis of the electrical and the control components they are just secondary. Good operating mechanical air-conditioning system is just responding to commands from the electronica sensors that get sent to a PCM that follows instructions that sends out a signal that commands the compressor to operate at a certain speed depending on the load. The other mechanical components separate from the AC system or would control your dashed duct airflow to the defrost to your face or to your feet this will separate into a different mechanical category what also has electronics controlling it. This area I do not have a lot of experience in because even I have not had too many problems with Prius myself and I am very fortunate to work with Luscious Garage and San Francisco went all the labor that takes a long time for teardown and diagnosis I just pointed over to Luscious for them to handle that because they are capable and competent at working on Prius as an intermittent problems even for somebody with the right tools and training can be difficult and time-consuming. This area I do not have a lot of experience in because even I have not had too many problems with Prius is myself and I am very fortunate to work with Luscious Garage and San Francisco went all the labor that takes a long time for teardown and diagnosis I just pointed over to Luscious for them to handle that because they are capable and competent at working on Prius as an intermittent problems even for somebody with the right tools and training can be difficult and time-consuming.

    5: getting back to Toyotas procedure if I remember correctly saying the system had to be topped off and add dye. This is a no go and not a recommended procedure in anybody’s book you do not top off the electric compressor systems or any R134A AC system. You only completely drained the refrigerant and Way in the factory specified amount with no exceptions to this rule.You only completely drain the refrigerant and weigh in the factory specified amount with no exceptions to this rule.

    6: Another recommendation no automotive shop should be allowed to try to diagnose a complicated intermitted problem with a hybrid system without the factory software like Toyota TechStream. Of course someone can do it if they actually read the manuals and understand the motive operation and their skilled in electrical diagnostic procedures of back pinning and reading signals in and out of components but very few shops can do this reliably.

    7: honestly I would not myself want to work on this vehicle after this many attempts to repair it telling you it will be costly and possibly time-consuming and frustrating. But it could also be something that was very simply overlooked.
    Unfortunately for your 2004 Prius the expansion valve is located under the dash at the evaporator which as you know is roughly a seven hours of labor. This must be replaced after a compressor burn out. But somebody can gamble and decide to try it without replacing but if you ask me to guarantee it I will tell you absolutely zero guarantee whatsoever no if and’s or butts about it. Also the condenser gets replaced and every other component line hose gets flushed out.
    If the shop repairing your vehicle was recovering recycling and recharging your vehicle the first thing I do is use my refrigerant analyzer to test the quality of the refrigerant. Many private shops even the dealerships I find that their refrigerant sometimes is contaminated with other refrigerant or high percentage of air mixed in with the refrigerant. And unfortunately they never replace their receiver dryer filters inside the recycling machine so there is often high moisture content in recycled refrigerant coming from automotive shops.

    8: Reading your description and your text and your series advance that you described in your first post. Without me having to go back and read all that if a second compressor failed with a burnout and only the compressor was replaced this is a very bad procedure, on any compressor burn out where there’s particulate Metal debris that left the compressor it will be in the condenser and very micro fine particles of metal filings like 3000 grit sandpaper will be suspended inside the oil.
    So once your system can be confirmed mechanically and refrigerant level sound and operating then other diagnosis on control components can be performed.
    If the system is ran too low or too filled with refrigerant or hasn’t high air content and the compressor is overheating you don’t want the system shutting down thermally or over amping.

    This is where somebody would break out their text stream and start commanding the duct airflow to change positions to see if electrically everything is working properly through the commands mechanically watch that every door or flap opens and moves to its correct position. Even if the technician had to mechanically circumvent an override or disconnect something to make the air flow come out of the face duct vents.
    Take note air-conditioning system with sensors is very difficult to keep running in cold weather conditions during winter time and may confuse a technician why he cannot get a system to stay running. If I was in a cold location where the outside temperature was in the 40s or even the low 50s or below. You may have to even put a piece of cardboard over the engine compartment to funnel the hot engine heat through the crowd grill intake air fresh air mode to put a load of hot air over the evaporator to keep the AC compressor running. In cold climates you may even have to put one of those propane bullet heaters in your shop pointing the hot air towards the front of the grill so the condenser gets roughly 75 or 80° warm air flowing across the condenser to keep it running in a steady state so you can constantly perform your test without worrying about the compressor cycling off.
    Forcing the air-conditioning electric compressor to run using software on a cold day is not a good thing that does not give you the same condition as the air conditioning running under load so your pressures would not be normal and you can cause some false triggering of codes or misdiagnosis.
    This is where having Toyota Techstream and driving the vehicle down the road data recording all the input and output of the sensors and the commands going to the compressor at the same time you read the low side and high side pressures and temperatures from the sensors located in the transducers and temperature sensors built-in to the vehicles air-conditioning systems.
    Performing the cardboard trick I mentioned above putting the piece of cardboard over the engine compartment to funnel the hot fan air from the radiator into the evaporator this is where the Bluetooth temperature gage is I have the software on my phone made by Fieldpiece or Testo come into play because you move the cardboard around and place the Bluetooth temperature sensors down just above the passenger compartment air filter this is the point of where the air is mixed in the true temperature can be taken. Performing the cardboard trick I mentioned above putting the piece of cardboard over the engine compartment to funnel the hot fan air from the radiator into the evaporator this is where the Bluetooth temperature gauges I have the software on my phone made by Fieldpiece or Testo come into play because you move the cardboard around and place the Bluetooth temperature sensors down just above the passenger compartment air filter this is the point of where the air is mixed in the true temperature can be taken.
    Some technicians will take this method out of context and not understand what they are doing and because they don’t have sensors to measure what they are doing they could be feeding 120 or 140° air right down the air intake to the evaporator overloading it with hot load of air giving you false pressure readings but the technician does not know this is happening. The technician must measure and data record everything and actually understand what you’re reading.

    9: did this vehicle ever incur any water intrusion or flood damage even worse yet salt water.
    Was this vehicle salvage title where wiring and loose grounds paint work, where they remove ground wires painted over metal and then put the wires back over painted metal so you have bad ground and you have a potential voltage drop intermittently.

    110% sure that your 12 V battery is in tiptop condition.

    10: with all your symptoms and attempted repairs if this came in to the shop to me unfortunately one of the things that I would recommend as my first diagnosis is to 1: recover the refrigerant out of your system
    2: remove your compressor to see the quality of the oil condition metal flakes or burnt.
    2a: Oil balance when discharging the refrigerant system a specific certain quantity of oil on a properly charged refrigerant system with the proper amount of oil will be left inside the compressor this needs to be confirmed not too much not too little.

    2b: if the oil is clean and the correct amount is removed from the compressor now the compressor can be replaced properly evacuated until the system is dry way under 500 µm then properly recharge the refrigerant with clean dry pure refrigerant by weight.

    Now after all this the system can be tested properly to confirm good mechanical operation of just the mechanics of the physical air conditioning components i.e. expansion valve and compressor control systems and electronics are separate and different tests not related.

    Sorry not much help. This car had too much guess work and shotgun component replacement and procedures. Now other than the underlying original problem very highly likely there is technician induced problems or intermittent problems on top of the original. It’s the man-made problems that are the hardest to diagnose because they were never originally faults in the first place that could naturally happen.

    location San Francisco and I would recommend and direct you to take your vehicle to Luscious Garage in San Francisco I would be doing the initial inspection and confirming the mechanical soundness and fitness of the air conditioning system. I would leave the long labor us diagnosis and crawling under the dash and scanning up to the technicians at Luscious Garage who I would be working with side-by-side as they need me.

    I have so much work I cannot be tied up doing diagnosis or Mechanically replacing parts because I’m a subcontractor around the San Francisco Bay area to roughly 1200 shops over the last 27 years
     
    SFO likes this.
  6. LEARNER

    LEARNER Junior Member

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    No salt water intrusion or salvage title. I am the original owner.

    I did do ac self diagnostics months ago and got 21. 76 and I think 43 but the last one dissapeared when I checked yesterday 1-5-20. I know 21 is because the solar sensor doesn't see enough sunlight.

    Very helpful info you gave.

    I've been following LG's blog posts for years and they have amazing insights and experience.

    Yes the first shop was clueless and had a gut feeling they probably didn't use the right fluids or didn't fill them correctly with all the warning lights and multiple revisits and charging me pro rates. Very Bad decision going there.

    That Import Direct AC Compressor from Oreilly's Parts may not even be compatible as advertised.

    Yes I thought starting over would be a good start to evac and refill and go from there.

    Temps here in the Southeast coast beach area randomly get high. Other day up to 75. Will pass on cardboard trick.

    I did locate one shop that works on hybrids one of which has consistent good reviews and no teriible reviews (I read them all looking for phony ones too) Will go talk face to face and see how he acts as I am getting more careful in who I work with. There is another too. Having a National warranty would be great as I travel all the time but Professional work is the priority.

    I gave up on Toyota after 4 visits plus the fast food style not conducive to thorough diagnostics.

    Thanks so much for enduring my long winded post and your thorough reply which I will reread several times and study.

    Like they say at the VA constantly ,Thank you for your service. :)
     
  7. LEARNER

    LEARNER Junior Member

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    Thanks again. Was that a typo on best coast? :) I do love it out there. You got the views.

    Oh and 12 volt battery well within limits on self diagnostic.
     
    #7 LEARNER, Jan 6, 2020
    Last edited by a moderator: Jan 6, 2020
  8. LEARNER

    LEARNER Junior Member

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    Hey you may not remember by intermittent AC failure problem which does work most of the time.

    Update: I put the problem on the backburner as the weather was getting cold and seemed to work without any problems except randomly as long as you keep on max cool and don't drive the car hard.

    Trying to get fixed now and talked to 2 separate Prius Techs experienced on AC system separately and gave all the symptoms with the suggested diagnostics the same as yours.

    The both though mentioned experiences having problems using after market non-oem AC compressors on the Prius causing a number of head scratching problems like mine that were resolved when they installed an oem Toyota AC compressor.

    Have you ever experienced this or heard of it?

    The only self diagnostic code left is 76. The other code 42 maybe 43 did go away when I rechecked months later. I looked up the extended code which had something to do with servo air mix door which Toyota replaced so maybe it was malfunctioning.

    The 76 code indicates either bad compressor, condensor fan circuit problem , inverter overload or something like that.

    I'm tempted to just replace the compressor with an oem one and cross my fingers but not finding enough evidence online in multiple searches of after market ac compressors not working right in the Prius.

    Although the original oem compressor failed and was replaced with an after market one then a year later it stopped working then replaced with the Oreilly's Import Direct AC Compressor then that failed a month later and replaced with another Oreillys Import Direct AC Compressor the one I have now that blows very cold air most of the time although when the temp gets up above 86 degrees it starts going out more often and you have to park it and turn off in the shade for 15 minutes or so and turn back on and it will work again.

    Use to be you turn off and right back on and it would work somehow resetting it but maybe which I can still do in cooler weather. One day it;s cold here and one day it's in 80's.

    Remember the Toyota servce manager in the 4th visit saying they found no leaks in another dye test and claimed they recharged as the did before and that it must be an internal leak and bring it back in a couple of months.

    Every Hybrid mechanic I've told that to claims BS.

    Toyota checked the compressor out they said and it checked out ok but I'm thinking on it's own it may check out but as far as meshing with the Prius AC system control module or head or whatever it's called it's just not compatible competely.
     
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