Fixed: 2004 LX470: AC compressor not engaging with self diagnostic code 21 & 23

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Aug 27, 2018
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With the 100+ degree sunshine in AZ, AC won't turn on. The last time using the AC was last year.

By looking at the compressor, I believe the clutch didn't engage at all.

Also did a self diagnostic test by:
Hold the AUTO and Recirculated air button while turning the key from OFF to ON​
And got code: 21 & 23.


While 21 is for the solar sensor which I guess could be ignored, code 23 is regarding pressure switch circuit.

What could be my next stop of troubleshooting?

Thanks!
 
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Mar 22, 2017
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257
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Camarillo
With the 100+ degree sunshine in AZ, AC won't turn on. The last time using the AC was last year.

By looking at the compressor, I believe the clutch didn't engage at all.

Also did a self diagnostic test by:
Hold the AUTO and Recirculated air button while turning the key from OFF to ON​
And got code: 21 & 23.


While 21 is for the solar sensor which I guess could be ignored, code 23 is regarding pressure switch circuit.

What could be my next stop of troubleshooting?

Thanks!
Same code appears on my 2004 Lx after nav delete, was a coincidence. Had to replace the fan clutch relay which is built into the the whole fuse block in the engine bay. Was quoted $700 for the part by the shop, picked it up from Mcgeorge toyota for $500
 
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got techstream? or can you manually trigger the clutch? First though, check pressures.
you should run it in auto and not let a year go by without using it. If only because you could be driving around with zero r134 for a long time before you notice it. That will just cost a ton more dollars.
 
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got techstream?
you should run it in auto and not let a year go by without using it.
Yes, I got the TechStream software and adapter. What particular setting or data I should look there?
I knew I should enjoy it more often. However my work location changed and the LX stayed in the valley.

I read somethere that low pressure will disable the compressor and mentioned the glass sight to inspect the refrigerant volume. Since the compressor doesn't run now, it's impossible to perform this inspection? I don't have a manifold gauge either.
  1. What's the easiest way to check if there is enough R134A in the system? Maybe buy a charging can with gauge?
  2. How to verify if the compressor and clutch still working? Like short PINs on the pressure switch to temporarily engage the clutch?
Thanks!

1589051714472.png
 
Joined
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Same code appears on my 2004 Lx after nav delete, was a coincidence. Had to replace the fan clutch relay which is built into the the whole fuse block in the engine bay. Was quoted $700 for the part by the shop, picked it up from Mcgeorge toyota for $500
$500 for a new whole fuse block? Hopefully not my case. Was the compressor working at that time?
 
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without knowing the state of charge everything else is irrelevant. plenty of charging, pressure threads on here.
 
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without knowing the state of charge everything else is irrelevant. plenty of charging, pressure threads on here.
That's exact what I want to figure out as my 1st step. Doing my research right now and there are indeed lots (if not too many) of AC threads here.
Just cross by the following:

So before I invest a vacuum pump and a manifold gauge, what's the best way to check if the system still have charge?
 
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$500 for a new whole fuse block? Hopefully not my case. Was the compressor working at that time?
My local mechanic with a good knowledge in AC SYSTEM troubleshoot mine for $90. Best $90 bucks spend. Once he told me what’s wrong I replaced what was recommended to replace. Of course I asked him specific questions like does it need charging or is the compressor functional? Did test the compressor or did you bypass the relay to confirm?
 
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Eventually I purchased a set of manifold gauge, and measured both L and H said pressure is 0. So guess all refrigerant has leaked. Could I just charge it? Or have to use vacuum pump? Do I need to add compressor oil?
 
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Pretty much answering my own questions.

So I did get a vacuum pump as I thought I should figure out why the AC system was leaking. After hook up the manifold gauge and vacuum pump, immediately noticed the system couldn't hold the vacuum, and the negative pressure went back to 0 progressively once the pump is off. Apparently it's leaking somewhere.

Then thought to try the laziest troubleshooting, and hoped it could just leak at the L/H port. Poured a little bit oil in one port and vacuum the other port. However, the oil didn't get sucked in either port. So the valve core must be good.

The next thing I did was to remove the L port valve core and added some UV dye. Then just tried to recharge the system with the left-over can of R134A from 5 years ago. During the charge, I heard the sound of air leaking from the front of the car, and eventually found it's leaking between the condenser and the discharge pipe. BINGO! Hope this is the only leaking.



3. Leaking between Condenser & Discharge Pipe - 0.jpg
 
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Removed and inspected the O-Ring is badly compressed. Purchased Part # 90069-08007 for $0.63 at local Lexus dealer.

Replaced the O-Ring, and screwed it back (7 ft-lbf).

Retested with the vacuum pump and it held the negative pressure over the night!!!

Now it should be ready for recharging...
 
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Questions:

1. The correct amount of R134A:
The 2004 LC100 FSM said it should be 37.03 oz:​
1590074768652.png
However, the forum mentioned 28oz, like: No AC FAQ ?
So what is the correct amount for 2004 LX470?​
BTW, I didn't find the label on the car. Where should I look for it?​
2. Preventive Maintenance items
Is there any thing I should also replace, like O-Ring, before recharge the system?​
Looking forward to hearing any suggestion. Thanks
 
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Regarding the amount of R134A to charge, eventually I found the label on the engine hood saying Max. 1100g Min. 1000g, which is same as on the FSM.
So it should be 37oz.

1590076175793.png
 
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So yesterday I did the full charge of R134A, and finally got the AC blowing cold air under AZ sun.

I was glad that I took the optimized H side liquid charge + L side gas charge, which reduced the charging time significantly. Also, the H side liquid charge with engine off would also boost the system with enough refrigerant to engage the compressor when starting the engine.

Glass Sight shows 0 bubble once charging to the factory spec of 1100 g of R134A
1590165992472.png


With both FR and RR AC to Max Cold, my final pressure with 90 degree air temperature is: L 37 psi and H 165 psi. Not sure if it's in the range.
1590166038615.png
 
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When I started this thread, I was hoping to get some quick recommendation and/or first hand experience to save time to get the AC back as soon as I can, since I didn't have much experience on AC system and not quite comfortable to work on it. While I did get the tips to check the pressure and to research the plenty of charging/pressure threads, it's pretty painful to go through hundreds of threads and then combined pieces of information together to get a better picture. The learning curve can be more productive with words from experienced people.

Maybe it's so obvious to lots folks here, I'd still like to summary all my experience of fixing my issue in one thread, with the hope to save you tons of hours and frustration finding the way out.

* The following procedures only tested on my own LX470 and YMMV. It's listed here for your reference only. DO NOT FOLLOW THIS PROCEDURES!
* It may damage your car or cause body injury. Please do your own research, follow the official factory procedures and seek the assistance from certified professional mechanics.
* It is illegal to vent 134a refrigerant into the atmoshpere.


Symptom:
  • AC had no cold air;
Visual Inspection:
  1. Confirmed the compressor wasn't engaged with AC on, by looking at the front end of the compressor pulley which didn't turn at all
  2. Checked the Glass Sight and couldn't see through the glass at all. I even though the glass may have been worn
  3. Did the self on-board diagnostic, by holding the AUTO and Recirculated air button while turning the key from OFF to ON. And it showed code 21 & 23
  4. Code 21 is for the solar sensor which I guess could be ignored, and code 23 is regarding pressure switch circuit which was the concerned area
  5. Per my reading, lower than 28 psi at L or suction side pipe will cause the pressure switch turn off the compressor for protection
  6. At this point, the next step is to get the tool to start the actual troubleshooting
Troubleshooting:
  1. Bought a set of manifold gauge, and confirmed there was 0 psi from L and H ports.
    • So it must be leaking somewhere.
    • It was a better news to me as I was thinking the compressor was shot
  2. The next logical step is to charge the system with UV dye, with the hope to:
    • Detect the leaking location, and
    • Confirm if the compressor (along with the pressure switch) still working
  3. Before charging the system, need to do the vacuum test to confirm if there is leakage.
  4. Loan the vacuum pump from Autozone, and hook up to the yellow hose.
  5. Ran the vacuum pump for half hour, and noticed that could only get to -20ish...
    • Tips: The pump should have 2 size of connection port (1/4" and 1/2"). You will need to cap and seal the one not connected
  6. As soon as I closed both L & H valve at gauge, the gauge progressively returned to 0 psi in couple minutes.
    • Confirmed there was leakage
  7. The 1st location of leakage I suspected was the either L or H ports, since they open to air.
    • So I dripped a little bit compressor oil into one port , ie L, and then run vacuum pump through the other port, ie H
    • The oil didn't get sucked in, so assumed the valve core stem were good in either L or H port
  8. The next step is to detect the leakage along the whole AC routes. Because of the pretty steady quick leakage of vacuum, it made no sense to fully charge the system.
  9. Since my AC is totally leaked, and one of the best way is to use clean compressed air which is more environment friendly. However, I remembered it's mentioned somewhere it may not be good to the AC system.
  10. Not sure what's the next step, I went ahead to add some UV dye into the L port by removing the valve core stem.
    • You may add the UV dye through the gauge hose. However, my hoses are pretty thin and it's impossible to do so.
  11. Found a left-over can of R134A from 5 years ago which still held 2/3 of refrigerant under pressure. It's the perfect source of clean pressured gas (Sorry environment :frown:)
  12. With the engine off, I hooked the can to the L port. As soon as I open the valve, I heard the noise of pressured air leaking from the front end, where is the condenser.
    • I was lucky enough and my fingers felt the air flow right from the place where discharge pipe connects to condenser, as shown in floor 10.
    • BINGO! Here was the leakage!
$0.63 of Fix:
  1. Once identified the leakage, it's very reasonable to believe it had a failed O-Ring.
  2. Unscrewed the connector and visual inspected the O-Ring. It was in very bad shape and was compressed flat.
  3. Researched on PartSoug, and got the part # of 90099-14120. Called local Lexus dealer, and purchased the updated part # 90069-08007 for $0.63
    • When purchasing parts, I found Lexus 👍dealer is always cheaper than Toyota 👎dealer, as well as Acura 👍dealer is always cheaper than Honda👎 dealer.
  4. Replacing the O-Ring is pretty straightforward, and the factory torque for the screw is 7 ft-lbf.
    • Tips: You may remove the pipe holder on the top of radiator which holds the discharge pipe to make more room to work on the O-Ring
  5. Vacuum Test!
    • Now it can reach to -30ish
    • Left it over night, and it still held the -30 pressure
  6. Problem Fixed!
Full Charge Procedures:
  1. Now it's ready to recharge the system.
  2. Tools/Parts needed:
    • Manifold Gauge
    • Can Tap (Mine came with the manifold gauge)
      • Now days, all R134A comes with self sealing valve. You will need an adapter if you still have the old style can tap for piercing valve
      • ACME adapter (1/4" Male to 1/2" Female) if the hose didn't match the can tap (Mine comes with the gauge)
    • Vacuum Pump
    • R134A: 4 of 12 oz cans
    • PAG 46 compressor oil (only needs 2 oz)
    • Kitchen scale (will have a picture later)
  3. According to my reading, 1~2 oz of compressor oil may have lost for a fully discharged system.
    • It may or may not be true. It's impossible to know without draining all oil and then refill which sounds costly to me
    • Excess oil in the system will impact the AC performance. But lack of oil will damage the compressor.
    • So I could live with degraded performance but couldn't afford for a damaged compressor
  4. Again, I removed the valve core stem from the L port and pour in around 2 oz of PAG 46 oil.
    • You may do it through the hose.
    • However, my hose is too thin to put in oil
  5. Before charging, I researched that the factory spec requires 1000 g ~ 1100 gram of R134A which is more than 37 oz. So ordered 4 of 12 oz can.
    • Considering the refrigerant lose by bleed and left over in the hoses, you really should prepare a little bit more than the spec.
    • I decided to charge to the max of 1100 gram to compensate the left-over in the hoses
  6. As far as the correct procedure of charging, most of guides/videos follow the normal gas charging through the L port. However, per my research (also confirmed in FSM), there are actually 2 ways:
    • Liquid form of charge through the H port
    • Gas form of charge through the L port
  7. I decided to do the 1st can in liquid form and the rest cans in gas form, for the following benefits:
    • Liquid form of charge keeps the engine (so the compressor) off, and should add enough refrigerant (and pressure) for the next step which runs the engine (and the compressor) to avoid possible "dry run" of compressor
    • Liquid form of charge is very quick within 1 minute
  8. Step 1: Deep Vacuum
    • Run the vacuum pump for at least 2 hours.
    • The purpose is to remove as much moisture from the system as is possible.
    • When done, close the both L & H valves at gauge. Leave the L & H valves open at the coupler
    • Turn off the pump and disconnect the yellow hose from the pump
    • Keep eyes on the gauge and it should hold the vacuum while you are preparing the next step
  9. Step 2: 1st Can - Liquid form of charge
    • WARNING: ONLY PERFORM THIS STEP ON FULLY LEAKED AND VACUUMED SYSTEM!
    • WARNING: ONLY PERFORM THIS STEP ON FULLY LEAKED AND VACUUMED SYSTEM!
    • WARNING: ONLY PERFORM THIS STEP ON FULLY LEAKED AND VACUUMED SYSTEM!
    • Keep engine OFF; Keep L & H valves at gauge closed; Keep L & H valves at coupler open
    • Securely connect the can tap to the yellow hose (hand tight only)
    • Screw on the 1st can of R134A, and open the valve at the can tap
    • Bleed the air from the yellow hose
    • Using the kitchen scale, weigh the can
      • Notes: you should always weigh the can in the same way/position
      • When the can is empty, it's pretty much impossible to keep it upright on the scale. So you have to lay down the can. Hence, recommend to weigh the can in lay down position instead of upright from the beginning
    • While holding the can upside down, open the H side valve at gauge ONLY!
    • You should see liquid pass thru from the gauge window, and could feel the can get emptied within 1 minute.
      • The can will be cold!
    • Close the H side valve at gauge.
    • Close the valve on can tap.
    • Weigh the can in the same way/position
    • Unscrew the can from the can tap
  10. Step 3: 2nd Can - Gas form of charge
    • Screw on the 2nd can
    • Open the valve at can tap
    • Bleed the air from the yellow hose
    • Using the kitchen scale, weigh the can
    • Open all doors
    • Turn the key to ON position without starting the engine
    • Set both FR & RR AC control to
      • AC ON
      • MAX COOL
      • Air inlet control to RECIRC
      • Fan speed to HI; Open all doors/windows
    • Start the engine
    • Now watch the compressor, and the front end of pulley should be running together meaning compressor is engaged.
    • DO NOT TOUCH ANY H SIDE VALVE FROM THIS STEP FORWARD!
    • Keeping the can in upright position, gently open the L side valve at gauge and watch the L gauge rising
      • Keep the L gauge below 60 psi
      • My hose is thin (1/4') and has valve core). So even I fully open the L valve, the gauge barely went above 40 psi
    • For the same reason of small hose, the charge went very slow. So I have to place the can around the radiator fan to heat it (see picture below)
    • DO NOT INVERT THE CAN AND KEEP IT UPRIGHT!
      • Otherwise, liquid may get into the L/suction side of compressor with the risk of "snagging"
    • When the can is empty, close the L side valve at gauge.
    • Close the valve on can tap.
    • Weigh the can in the same way/position
    • Unscrew the can from the can tap
  11. Step 4: 3rd Can - Gas form of charge
    • Repeat the previous Step (3), except for those steps touching engine and AC controls (keep engine running and AC controls)
  12. Step 5: 4th Can - Gas form of charge (touch up)
    • Screw on the 4th can
    • Open the valve at can tap
    • Bleed the air from the yellow hose
    • Calculate how much R134A still needed to charge to 1100 gram
      • In may case, I still needed 177 gram from the 4th can.
    • Using the kitchen scale, weigh the can. This time, we may keep the can upright on the scale.
    • Follow the same procedures as 3rd can, and charge to the weight.
      • Check the weight frequently to avoid over charging
    • Once done, close the L side valve at gauge.
    • Close the valve on can tap.
    • Remove the can from the can tap.
    • Feel and enjoy the ice cold air in the cabin
    • Monitor the L & H gauges for a while.
  13. Step 6: Clean up
    • Make sure all valves (at coupler and at gauge) are closed
    • Turn off engine
    • Disconnect the couples from the ports
      • It may be hard to disconnect the H hose, because of the high pressure in the hose.
      • While keeping all other valves closed, slowly open the H side valve at the gauge to release a little bit pressure from the hose, until it could be disconnected.
      • The H couple may be very hot! Watch out or wait for it cooling down
All set!

The following thread gave me lots of information. Thank the contributors.

The following picture show how I set up the gauge and scale.
1590183725988.png


The following pictures shows how I set the can to be heated by the radiator fan. Be careful, and hand hold it in upright position all the time.
1590183827371.png


This picture shows the Glass Sight is free of bubble and can be easily seen through.
1590183886280.png
 
Last edited:

BadReligion

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Nice work and write up. You will appreciate your AC that much more every time you switch it on. The 37oz of refrigerant is likely for LCs with rear air, as opposed to the 28oz mentioned in the FAQ thread.
 
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Black marks on this gauge set are marked at fsm spec ranges.
This is my dedicated LC hose tree. Picture taken at 85 degree high humidity every time. Just a tiny crack open on a 4th can of 134 from full vacuum.

IMG_20190706_072229.jpg
 
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