01 LX470 AC Woes (1 Viewer)

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tyl3rd

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Hey folks,

Looking to get some advice here about my 01 LX470. AC just went out. AC button is flashing, and I can hear what sounds like the compressor grind briefly (maybe 2 seconds) and then shut off when pushing in the AC button. I tested the pressure at the fill spot left of the engine and it was reading 95 PSI which seems way too high, but I think that is because the compressor won't turn on. All was working normally earlier today (and nice and cold). I have the physical buttons and not the navi unit where air control is integrated. I'm unsure of how to pull any codes, and didn't see anything obvious in TechStream (but admittedly, unsure of what to be looking for). I'm a complete novice when it comes to AC systems so wondering if folks have any troubleshooting tips or thoughts or if better to just take it to a shop.

Cheers,
Tyler
 
To check A/C codes.....turn key to ON and press the AUTO and RECIRCULATING buttons at same time. A code will appear on digital screen. Then go from there based on code number. Could be magnetic relay, speed sensor, bad clutch and anything else that @flintknapper says it is.

Also, you can use a mulitmeter to test the ohms resistance at the plug connector of the compressor. If the resistance is not in the proper ohms range as per the factory service manual, then you need a compressor. Ask me how I know that little nugget of info.
 
I mean screen where temperature reading is
 
tyl3rd said:
Hey folks,

Looking to get some advice here about my 01 LX470. AC just went out. AC button is flashing, and I can hear what sounds like the compressor grind briefly (maybe 2 seconds) and then shut off when pushing in the AC button. I tested the pressure at the fill spot left of the engine and it was reading 95 PSI which seems way too high, but I think that is because the compressor won't turn on. All was working normally earlier today (and nice and cold). I have the physical buttons and not the navi unit where air control is integrated. I'm unsure of how to pull any codes, and didn't see anything obvious in TechStream (but admittedly, unsure of what to be looking for). I'm a complete novice when it comes to AC systems so wondering if folks have any troubleshooting tips or thoughts or if better to just take it to a shop.

Cheers,
Tyler
Click to expand...
^^^^^

Yes, just take it to a shop. Your low side reading was 95 psi because you were reading the 'static pressure' or saturation pressure. That figure 95 psi would be about correct for an ambient temperature of roughly 85°F.
 
@flintknapper

My local trusted independent can get me in next Wednesday for diagnosis. If anyone has anything to try and look for taking it in I’ll be happy to check it out. I’m not completely helpless wrenching just never worked on AC before.
 
How accurate are the go/no go gauges from Autozone’s recharge bottles? If the a/c is weak but doesn’t need refrigerant is there a fix without getting a new compressor?
 
tyl3rd said:
@flintknapper

My local trusted independent can get me in next Wednesday for diagnosis. If anyone has anything to try and look for taking it in I’ll be happy to check it out. I’m not completely helpless wrenching just never worked on AC before.
Click to expand...

Understood. And we've no doubt you are not 'helpless'. 👍

It is just hard to diagnose AC issues over the internet. But....the short 'grinding' sound just before the unit shuts down could be the compressor trying to 'seize'. Because your engine utilizes a serpentine belt (to run accessories like your alternator, PS pump, engine cooling fan, AC compressor) you don't want it to fail if a component were to hard fail (seize). To that end.....Toyota installed a shut down switch on the back of the AC compressor.

When/If it senses an appreciable difference between engine speed and AC clutch speed....it assumes the compressor has seized (or is trying to) and it disables the circuit to the AC Clutch (resetting after each shut down). So its possible this is your issue.

It IS something you can check, but its not a lot of fun getting to it. There are other possibilities....but an experienced shop should be able to find the problem pretty quickly. Whatever the reason....its not likely to be a quick/easy fix for a DIYer is why I recommend taking it in.
 
LXfromTX said:
How accurate are the go/no go gauges from Autozone’s recharge bottles? If the a/c is weak but doesn’t need refrigerant is there a fix without getting a new compressor?
Click to expand...

There are just SO many reasons why an AC system would not be performing up to standards. It could be a single issue (low on refrigerant) to several contributing issues. Most troubleshooting efforts will begin with checking the system's high and low pressures (assuming the compressor will engage). This is best accomplished with a set of manifold gauges.

I can only speculate as to the accuracy of the Go/No gauge on a refrigerant recharge can....but suffice to say it probably cost some company in China about .27 cents to build, so I wouldn't put too much faith in it. But worse....it only shows the pressure on the low side of the system. Ideally we want to see the high side pressure as well.

Those things are fine for situations where the system is otherwise sound...but just needs a bit of refrigerant. It would not use one in any way as a diagnostic tool however.
 
tyl3rd said:
Thank you for the guidance and explanation here! I appreciate it!
Click to expand...

Happy to help anyway we can.

Hope your issue is nothing too serious and that you'll have cool air again soon.

Please post back a follow up (when done) so that others with similar problems and symptoms might gain some direction.

Take care,

Flint.
 
flintknapper said:
There are just SO many reasons why an AC system would not be performing up to standards. It could be a single issue (low on refrigerant) to several contributing issues. Most troubleshooting efforts will begin with checking the systems high and low pressures (assuming the compressor will engage). This is best accomplished with a set of manifold gauges.

I can only speculate as the accuracy of the Go/No gauge on a refrigerant recharge can....but suffice to say it probably cost some company in China about .27 cents to build, so I wouldn't put too much faith in it. But worse....it only shows the pressure on the low side of the system. Ideally we want to see the high side pressure as well.

Those things are fine for situations where the system is otherwise sound...but just needs a bit of refrigerant. It would not use one in any way as a diagnostic tool however.
Click to expand...
Thank you. I cleaned my evap coils and condenser to no avail. Off to the pros.
 
Maybe try swapping MG CLT relay with an identical relay (MIR HTR) and see if AC fires back up.
 
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