AC not working/blows hot air

Tiny
2011RAV4
  • MEMBER
  • 2011 TOYOTA RAV4
  • 2.5L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 50,000 MILES
The AC just started blowing hot air! I was told Toyota AC are hard to diagnose. All the fuses look okay. The Freon was checked and said it was okay. A friend hooked up Techstream program and was able to turn the clutch on and AC was working but stopped as soon as the program was turned off! He said it might be the compressor. I just want to know if there is anything else I should check before I go out and get a compressor.
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Tuesday, June 19th, 2018 AT 2:32 PM

19 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good evening.

No, they are not hard to work on at all.

No, to the compressor. If he activated the compressor and it blew cold air then it is working.

It sounds like an electrical issue turning the compressor on.

Did you check all fuses with a test light for power on both sides?

Roy

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak
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Tuesday, June 19th, 2018 AT 5:33 PM
Tiny
2011RAV4
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Thanks for the response. I did check the fuses with a multi meter but I will double check them again with a test light and get back to you!
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Thursday, June 21st, 2018 AT 9:27 AM
Tiny
ASEMASTER6371
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Sounds like a plan.

Keep me updated.

Roy
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Thursday, June 21st, 2018 AT 10:31 AM
Tiny
2011RAV4
  • MEMBER
Hi, sorry it took so long to get back to you. I checked all the fuses with the test light and they all looked good.

I was able to get a couple of pictures from Techstream that might help you.

The first one is with the ac on full but the clutch not engaged.

The second one is when I forced the clutch on with Techstream.

I noticed the pressure going up a lot on the second picture so I shut the clutch off. Also, both the fans on the radiator did not turn on at all and the air was not cold. I checked both fan fuses and they looked okay. I did not test them with the light because they are 30 amp box type and not sure how to test them. Any help would be appreciated!
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Tuesday, June 26th, 2018 AT 11:47 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, that does not give me any pressure readings. I need pressure readings on the high and low side.

The AC may be off due to low Freon level or the low side pressure is below 20 lbs.

Roy
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Tuesday, June 26th, 2018 AT 1:01 PM
Tiny
2011RAV4
  • MEMBER
Okay. I will get the gauges from my buddy this weekend and let you know what reading I get.

Do you need the static readings and the reading when I have the clutch engaged in Techstream? Would that also be the reason the AC condenser fan does not come on? I thought it always comes on when the compressor turns on.
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Tuesday, June 26th, 2018 AT 3:33 PM
Tiny
ASEMASTER6371
  • EXPERT
Yes, both static and running with clutch engaged.

Roy
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Tuesday, June 26th, 2018 AT 3:34 PM
Tiny
2011RAV4
  • MEMBER
Okay. I got the gauges from a friend!

85 degrees outside temperature with car not running.

Low side 115
High side 175

Car running at about 2,000 rpm and manually turning on clutch in Techstream.

Low side 34
High side 255

Ran like that for a few minutes (both radiator fans were also on) then the high side just kept going up every time I turn the clutch on! I had to shut the clutch off in techstream!

I also got a trouble code of B1479.

I read that would be the code for the "flow sensor on the compressor".

I also read voltage for flow sensor should be above 3.8 when compressor is off. Mine was at 3.56.V. Could the sensor be bad?
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Tuesday, July 3rd, 2018 AT 10:58 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, from the static pressures, you need an expansion valve. That would also explain why the high side keeps going up.

You need to go through the wiring to find out why the compressor will not come on.

Roy
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Tuesday, July 3rd, 2018 AT 11:08 AM
Tiny
2011RAV4
  • MEMBER
Changing the expansion valve looks like a big job!

What about the trouble code of B1479. Would the flow meter cause the pressure to go up? I read about someone who had a similar problem on a 2010 rav4 with the clutch only going on with the Techstream program and they told him it was a bad compressor?
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Tuesday, July 3rd, 2018 AT 11:57 AM
Tiny
ASEMASTER6371
  • EXPERT
That is not possible. If you command it on, then the compressor is good. It is the signal that is not activating the compressor.

B1479. I believe this set because you commanded it on and left it on. Doing what you did was intended as a test with key on engine off, not leaving the compressor run while the engine is running.

Roy

B1479/79
Item Description
Symptom/DTC B1479/79
Descriptor
Manual Air Conditioning System
Probable Causes
Air Conditioning Amplifier
Flow Sensor (Compressor and Pulley)
Harness or Connector Between Flow Sensor And Air Conditioning Amplifier
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Tuesday, July 3rd, 2018 AT 12:54 PM
Tiny
2011RAV4
  • MEMBER
Thanks again.

Do you know if the expansion valve on my vehicle can be taken out from the firewall side?

I could not find any videos on my make and model specifically, but some other ones show the bolts to get it off can be accessed from the firewall side while others show having to take if off from inside the car!
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Tuesday, July 3rd, 2018 AT 2:07 PM
Tiny
ASEMASTER6371
  • EXPERT
It is done from under the hood at the firewall. Recover all the Freon, remove the bolt that secures the two lines to the expansion valve and then remove the two bolts that hold the expansion valve to the EVAP core.

Make sure you change the dryer as well.

Roy
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Tuesday, July 3rd, 2018 AT 2:15 PM
Tiny
2011RAV4
  • MEMBER
Great. Does not look too hard. Thank you for all your help! I will order the parts and report back when I get it done!
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Tuesday, July 3rd, 2018 AT 5:05 PM
Tiny
ASEMASTER6371
  • EXPERT
Great. Look forward to hearing from you.

Roy
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Tuesday, July 3rd, 2018 AT 5:08 PM
Tiny
2011RAV4
  • MEMBER
Hi, Sorry it took so long for me to get back to you! I changed the Expansion Valve and the Compressor still didn't turn on. After researching the problem so more I found someone who had a Lexus who had the same problem and also got the B1479 code. Toyota has a TSB about it T-SB-0084-13. The Flow sensor has to have 3.8v with the AC OFF in order to have the amplifier tell the compressor to kick in! (mine was 3.59v) Toyota recommend changing the compressor because they don't sell the Flow sensor! I was able to find the Sensor on ebay for $50 and decided to try and change it myself!

I had to take off the front bumper, ac condenser(replaced drier) and radiator to get easy access to the Flow sensor on the compressor ( you may be able get to the sensor by just taking out the radiator) . I took the snap ring off the sensor and tried to lift up the sensor but it was frozen and broke off when I pulled up on it. I had to use a chisel to get the rest of it out. I noticed there was a lot of what looked like white rust or corrosion there so I scrapped out what I could and sanded it down so the new one would seat properly ! ( maybe The white rust was making the sensor not read correctly?). I got the new one in and put the snap ring on and then I checked it with Techstream and got a reading of 3.86v.(above the 3.8v min needed)! My old one was 3.59v!

I put everything back together and charged the system and the AC works now. A lot of work for such a simple part! I read the problem is with many Toyota models and years starting in 2009! Crazy how they let the problem last so long without addressing it and making people pay for a new compressor!

I just thought I would let you know in case someone else runs into the same problem!

TSB https://static.nhtsa.gov/odi/tsbs/2013/SB-10061590-2280.pdf

Here's a couple of pictures of the before and after Techstream Flow sensor readings!
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Thursday, July 26th, 2018 AT 7:59 AM
Tiny
ASEMASTER6371
  • EXPERT
Good job.

I was more concerned that with the high going up to high, it would effect the signal voltage and that is why you had a bad reading with the old one.

If it did not change after the expansion valve replacement then the sensor was the next step.

Roy
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Thursday, July 26th, 2018 AT 8:06 AM
Tiny
2011RAV4
  • MEMBER
Just a clarification. The Flow Sensor needs to be checked with the AC off! Voltage has to be between 3.8 volts and 4.2 volts. If below that then the flow sensor is bad.

Thanks for all the help.
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Thursday, July 26th, 2018 AT 8:36 AM
Tiny
ASEMASTER6371
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Correct.
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Thursday, July 26th, 2018 AT 8:46 AM

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