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Hi,

I found out that my 2009 4WD RAV4 (manual a/c) has DTC B1479 code stored in the a/c unit and it blows hot air.
I'm thinking of applying the simple solution that I found on the Lexus club forum "RX350 2010/2011 Air conditioning DTC B1479 cheap solution" that has very good tutorial with pictures for RX350 with auto a/c.
For the RAV4 manual a/c I found a similar diagram but cannot find location of the AC amplifier connector E37.
Anyone could help?
 

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Mine is a 2010 RAV4 Sport and for the manual A/C the connector is E36 and it's a 28 pin connector. Pin 4 is FLOQ, Pin6 is S5-1 and Pin 10 is SG-3. Also the yellow wire on Pin 14 is IG+ (12V power) and Pin 24 is Ground. I made a voltage divider with 100K + 39K in series and put it across pin 14 and pin 24 and tapped around 4 volts at the junction of the two resistors and fed that to Pin 4 going into ECU. Cut the red wire (FLOQ Pin4) and attach 4 volts to the end going to the ECU and leave the other end of the cut wire coming from the flow sensor unconnected.
 

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Thanks, I've found the location of the amplifier and figured out that instead of 5V output for the sensor it has just 4.5V, so I've used it directly as the input instead of the sensor.
 

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Glad to hear. All these simple Op-Amp circuits that people have posted using LM741 don't work in a single supply configuration because it needs more components to make it stable, which is why I went with a simple voltage divider. LM324 is designed to work in single supply so I may try that at some point but the simple fix is working. Before the mod my compressor would come on after about 5 to 10 min of driving which makes me wonder if a slipping belt would cause the flow sensor to not output the higher voltage (3.8+ volts) initially.
 

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Thanks. Just curious why do they need the flow sensor in addition to the pressure sensor?
If the flow sensor data is used in the manual AC or it's needed for automatic AC temp control?
 

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Traditional compressors that use magnetic clutch don't have flow sensors if I am not mistaken. May have something to do with regulating the solenoid that increases or decreases the compression in the compressor by changing the tilt angle of the plate. I saw a youtube video of how these compressors work and it was pretty interesting. My only guess is that by defeating the flow sensor with this work around, we may be sacrificing some fuel economy. It's a crappy design if the whole compressor needs to be replaced just because of a failing sensor. My car has 45000 miles on it and the compressor should last much longer than that. Every time they add more stuff for fuel efficiency they create more failure points.
 

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If it's just the 5V voltage regulator and the rest of the AC amp is o.k. then there might be a way to build a small 5 V regulator on a board and feed the 5V to all the sensors that are powered by the AC Amp individually. Alternatively, you can see if you can pick up an AC Amp on Ebay from a salvaged vehicle. Mine was around $250 new. Good luck!
 

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Yes, that what I was thinking, to hook up a 12V to 5V regulator to the connector harness but was too lazy...
 

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Today I decided to replace my temp fix using a simple voltage divider circuit with one using LM324 as shown for my 2010 Rav4 Sport. My connector on the AC Amp was E36 and FLOQ (Pin 4), IG+/12V (Pin 14) & GND (Pin 24). I tried LM741 but it doesn't work in this application because it requires dual power supply and LM324 uses single supply. Not sure how others who claim to use LM741 got it to work with a single supply voltage because any offset or imbalance will cause the output to latch. Anyway, I tried this circuit and it works fine. I adjusted the trim pot to give me about 3.95 V. My original FLOQ input was 3.73 V and boosting it to 3.95 V put it in the 3.8V to 4.2 V range that the AC Amplifier is looking for.
 

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Nice hack! Well done!
 

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Hello Toyota Family,
Didn't mean to hijack this thread but since everyone is on the same page this would be an easy way to start and discuss my issue I been having since last summer of 2017 seeking for solution.


This is in related to my 4 Cylinder 2014 Camry having B1479 and blowing hot air, I took the car the dealer at first they told me its AC amplifier Part # 88650-06670 is not working; charged me $110 to install. And that did not fix the problem now they telling me i need to buy new compressor part number "88310-0R014" quoted me around $821.08 after tax + $385.00 in labor plus recharge ac system of $159.95=..total $1366.03


I believe compressor PART NUMBER used in camry is same as that of RAV4, I have attached my techstream flow voltage while car is running and AC on which is 4.18v and its same even if I turn off the AC voltage does not go up or down.


Can anyone please help me out and confirm me that our amplifier and compressor are the same and the solution mentioned on here are the same for 2014 camry, considering the age of the car I am not comfortable at all replacing the compressor if fix mentioned here is doable


thank you very much family
 

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My first suggestion is to get a second opinion or quote from an A/C shop other than the dealer. Especially after their throw-parts-at-it approach (with your $$$) didn't work.

I use google, rockauto.com or even eBay to crosscheck part numbers.

From slcidea's posts I'm assuming that QUFL is normally connected directly to FLOQ and with your voltage being within his 3.8-4.2 spec, that's likely not the problem. So that leaves us with questioning what (other than taking your money) leads the dealer to say the compressor+ needs replacing. I'd get as much test info as you can before going elsewhere.
 
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tdi200 your flow sensor voltage appears to be within the appropriate range. My understanding is that these compressors don't use a magnetic clutch and there's a voltage sent by the AC amplifier which adjusts the tilt angle inside the compressor that varies the refrigerant flow. Number of things including electrical wiring, thermostat could be causing this issue. I would rule other things out before the compressor. Look at this video on Youtube that describes how these new clutchless compressors work
. The AC amplifier sends a control signal to the compressor solenoid valve to regulate refrigerant. If the AC Amp was changed you may need to check the connector on the compressor to make sure it's good. There are two connectors, one is a 3-wire (Flow Sensor) and the other 2-wire (Solenoid valve). It's the job of the AC amp to supply the control signal to the compressor. Hope this helps.
 

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My first suggestion is to get a second opinion or quote from an A/C shop other than the dealer. Especially after their throw-parts-at-it approach (with your $$$) didn't work.

I use google, rockauto.com or even eBay to crosscheck part numbers.

From sleidea's posts I'm assuming that QUFL is normally connected directly to FLOQ and with your voltage being within his 3.8-4.2 spec, that's likely not the problem. So that leaves us with questioning what (other than taking your money) leads the dealer to say the compressor+ needs replacing. I'd get as much test info as you can before going elsewhere.
I did take the car to 2 different shop one clearly told me just to take it to dealer, other one mentioned the same thing that compressor needs to be changed
 

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My first suggestion is to get a second opinion or quote from an A/C shop other than the dealer. Especially after their throw-parts-at-it approach (with your $$$) didn't work.

I use google, rockauto.com or even eBay to crosscheck part numbers.

From slcidea's posts I'm assuming that QUFL is normally connected directly to FLOQ and with your voltage being within his 3.8-4.2 spec, that's likely not the problem. So that leaves us with questioning what (other than taking your money) leads the dealer to say the compressor+ needs replacing. I'd get as much test info as you can before going elsewhere.
tdi200 your flow sensor voltage appears to be within the appropriate range. My understanding is that these compressors don't use a magnetic clutch and there's a voltage sent by the AC amplifier which adjusts the tilt angle inside the compressor that varies the refrigerant flow. Number of things including electrical wiring, thermostat could be causing this issue. I would rule other things out before the compressor. Look at this video on Youtube that describes how these new clutchless compressors work . The AC amplifier sends a control signal to the compressor solenoid valve to regulate refrigerant. If the AC Amp was changed you may need to check the connector on the compressor to make sure it's good. There are two connectors, one is a 3-wire (Flow Sensor) and the other 2-wire (Solenoid valve). It's the job of the AC amp to supply the control signal to the compressor. Hope this helps.

Thanks buddy the video does make sense and gives me some insights thanks for confirming about the ac flow sensor voltage I have the same thread on Toyota nation asking for 2014 camry to give me their voltage info but have got no replies yet only thing I found only in regards of TSB was for 2012 and 2013 camry not sure if specs are same for the 2014


just Google this TSB and it will link you there T-SB-0084-13


again thank you so much for all the help you guys are pitching in specially when huge amount of money being used for repairs at dealership.


p,s the problem started last year the car didn't get out from the garage when winter started until summer was back and that was the time I drove the car and that is when I found out that the AC is not working anymore
 

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It could be the compressor with a bad solenoid valve in which case you wouldn't have any other choice but good to rule out everything else first. Also look at rebuilt or aftermarket compressor from RockAuto if that turns out to be the cause. Good luck! to you.
 

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It could be the compressor with a bad solenoid valve in which case you wouldn't have any other choice but good to rule out everything else first. Also look at rebuilt or aftermarket compressor from RockAuto if that turns out to be the cause. Good luck! to you.
Thank you sir, I will keep you guys updated
 

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Here's a quick scenario where I could have ended up in the same boat the dealer wants to put you in.
The A/C in my '01 F-250 had given me trouble for over a year. Seemed like it worked when I wanted too. And very well until it decided to take a break a few minutes later. An HVAC tech friend of mine and I had put in many hours trying to figure out its problem - including evacuating and recharging it last fall only to find out it had the same intermittent issues this spring. After hooking up several indicator lights in the cab to monitor it I finally determined that the compressor clutch wasn't engaging every time the system called for it. I fixed it for free by removing a shim and replacing it with a thinner toothed washer that I flattened with a hammer. Now I know the RAV4 doesn't have a compressor clutch but I wonder if the Ford dealer would've figured out that all I needed was a new clutch or would they have sold me your package - New compressor (with a new clutch), install and recharge labor - oh yeah - discharge labor first.
 
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b1479 Toyota code solved

b1479 Toyota code solved by me :D :D: wink

I can't share the youtube link in here because I'm new so go to youtube.com and paste this x7wlsf1q1Ks
 
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