srtsweep

Do you guys by chance know of any way to test the compressor? I could take it off, but i'm not sure of a good way to check it to see if it works.

cssnms

Hole in one of the air bags. The system is designed to shut off the compressor when there is a leak to keep from burning up the compressor. Order new bags, install and compressor will activate again.

GSGXNC

I bought my GX with the coil swap already done and I recently investigated my leftover components. There is an ECU reset that you may need to do for the system to try again. There are YT video that explain better than I can. If the compressor still doesn't run then you may have a problem beyond the bags.

If you do find that the problem is the bags alone and you switch to coils, I recommend adding helper bags inside the new coils with the OEM system inflating them. I just installed these in mine and I am able to get the benefit of auto-height control and I am able to adjust between the N and H positions. It doesn't reach the Low position because the springs are too long/strong without begin loaded down. Other than fuel mileage(which I doubt would be noticeable), I don't see any benefit in the low setting anyway.

srtsweep

Compressor from underneath the vehicle. I hopped under the vehicle today. The compressor looks pretty old and beat up. I can hear the solenoid click when I try to activate the system, but this never kicked on. I tried to see if I could get a reading for voltage when I tried to activate the compressor by going from N to HI, but couldn't ever get a reading. Not sure if that means no power is getting to it or i'm just not doing it right ( I did test it beforehand on a few outlets).

srtsweep

I tried the ECU reset but still get nothing. I can hear the solenoid clicking though so I am assuming some power is getting there.

I have thought about switching to coils. I will say I really enjoyed the ride with the air suspension however when I did have it. It was incredibly smooth. I may decide to go that route however if I think fixing the air suspension will just be too much money/work.

IanB2

I understand the draw of sticking with the air suspension, but I've never once missed it, and knowing there's nothing else waiting to fail back there is nice.

cssnms

You are over thinking this... Like I said, if there is a leak the compressor shuts off. Pull the air bags and inspect them to confirm. You can even inflate them with an air compressor to check for leaks. Then buy a set of bags off ebay, install and enjoy.

ALAN553

in my case with the leak, the compressor would shutoff when the truck fell to the bump stops, but by ignoring the symptoms, the compressor will run much more often, for longer times and eventually burn up,so if you intend to keep the air system...don't procrastinate or your will be out another $500 + for the compressor

se7enine

I've switched to the Dobinsons IMS lift kit and feel the ride is as good if not better than the air ride. My air ride was still working when I converted so eventually I'll remove the compressor and give it away.

danjasmus

Greetings,

I have had a 2006 GX470 for about 4 years. It had 105K then, 160K now. It’s my road trip/trout fishing/trailer pulling vehicle. Not a daily driver, but does see cross country trips, logging roads for fishing access, and occasionally pulling campers, boats, and uhaul trailers when my wife buys big things.

After having my right rear height sensor fail while traveling and fixed by a Lexus dealer, I experienced a similar left rear failure and replaced that myself. I still had bottoming out issues when pulling a trailer, so I replaced the air springs with Arnott after market parts. They seem really well made, and I do not regret the decision to salvage the air suspension. I have not had it bottom out when driving since, including while pulling a trailer. I think I have the main issues solved, but it still loses air when parked overnight. Next step was to replace the air hoses from air tank to L and R air springs, and from the air tank to the dryer. Still leaks overnight, but compressor fills it quickly when I start it up, and seems to maintain the correct level whenever driving. I am about to embark on a 5,000 mile trip soon, and want to get it as good as I can. A few questions for the air suspension pros:

1). Is the air suspension system meant to be ‘air-tight’, or is some leakage normal, and allows the vehicle to rest on the axle bump stops when sitting? Much of my bump stop rubber is gone from bottoming out, so it sits really low.

2). If the system is supposed to be air tight, where is pressure maintained? My guess is at the air tank. When I remove the individual air hoses from the fittings (while on jacks!), it relieves the pressure from the air springs. When I removed the air hose from the air tank to the dryer, it did not seem to lose pressure.

3). Has anyone used a non-hardening silicone on the air hose fittings to try and maintain pressure in the system? Sparingly, of course! Pros/cons?

4). I have not closely inspected the front suspension because it has not been a problem, but does the GX have air suspension in the front too? I saw it referenced in another thread on this forum…

5). I noticed that during my repairs at one point that my compressor stop working. I thought it was toast. I plugged in my Foxwell OBD computer with Lexus extensions and I had a code for “compressor ran continuously for more than 100s”. I erased the code, and it started working again. Does the ECU or relay shut it down to prevent it from burning out? I was greatly relieved 😅

6). If the system is not intended to be completely air tight, does the compressor engage as needed to maintain the proper height and pressure?

Thanks for reading. I look forward to your replies. /Dan


With the replacement parts I am in for ~$500. I don’t regret it. If I still have leaks I may consider continuing to work backwards.

ASE

... the compressor maintains air pressure ... unless there is more than a superficial (very slow) air leak where it cannot compensate.

Independent of your Air Bag situation ... I strongly recommend replacing the anemic OEM Bump Stops with Timbren Bump Stops. These provide significantly more cushioning versus the OEM ones ... and will save you if for some reason your air bags lose all pressure.

... and NO ... do not use any sealant.

... and NO ... the front suspension does not have Air Springs. The air spring is specific to the rear to height adjust for towing (tongue weight) ... and to height adjust for rear seat passengers and weight in the cargo area.

chiph9

There should be minimal air loss in the system. Certainly none overnight, to where it's on the bump stops in the morning. During the pandemic I sometimes wouldn't drive it for 3 or 4 days and it didn't drop. You still have a leak somewhere.

There is a valve body that controls where the air from the compressor is directed (contains valves for left & right sides). Perhaps one of them is leaking. Spritz some soapy water over the fittings. But it's also possible an internal seal has gone bad and it's slowly letting air back through to the compressor. To test this, remove the pipe from the compressor and put a heavyweight balloon over the end of the pipe. If it inflates after several hours you'll know it's the valves.

No air springs on the front - they are steel coils. The LX is the model that has air/hydraulic all around.

I am not sure if the compressor runs to maintain height after the body computer goes into sleep (normally 10-15 minutes after the last door was closed) My garage is next to my office and have not heard it run (but to be fair, it's not a loud compressor)

The valve body doesn't appear to be sold separately, but as part of the reservoir assembly. There are two different part numbers: 48930-60020 is for standard suspension and 48930-60030 is for KDSS vehicles.

https://www.mylparts.com/oem-parts/l...bly-4893060020

https://www.amayama.com/en/catalogs/...to-leveler-154

Chip H.

hibby50

Hi all, I could use some help fixing my air suspension. I am not interested in a spring conversion (yet) I just got a gx470, and the drivers side was lower than the passenger. Both bags were replaced with Arnott bags. but I am still having the following issues:

1. The passenger side is jacked to full height while the drivers side is maybe 3 inches off the bump stop
2. When I try to lower the suspension, it does not exhaust air most of the time (at one point after a reset or some height sensors adjustments it was)
3. there is a leak somewhere which causes the truck to leak to its bump stops on the drivers side overnight (looked with soapy water but could not find anything, not the biggest problem right now)

I thought it may be the height sensors, so I removed them and measured the resistance. There was a smooth change in resistance throughout the whole range of motion.

I then adjusted the sensors so that the passenger side was at the bottom of the bracket on the trailing arm(?) and the drivers side was at the top, an an attempt to level it out, but nothing changed.

I am starting to suspect there is an issue with the reservoir solenoids for 2 reasons:

1. When I removed the passenger side air line, the driver side deflated as well
2. With both lines disconnected and the compressor running, air was only coming out of the passenger side

I don't want to throw parts at this, Is there a way I can test/inspect/clean/repair the reservoir rather than buying a new one?

ALAN553

its usually the air spring, you may not find the pin hole...it closes up depending upon how much inflation there is....but...its usually them

hibby50

In this case the bags are brand new, I suspect the push fitting that Arnott uses, but I don't have a mirror handy to see the top well enough.

Despite the slow leak somewhere in the system, there is still the issue of uneven height I have