Lwalters

Ok so I've been doing some research about the air ride on my 2003 GX470 and have not been able to figure out what's up with mine. Here is what's going on. When set at normal the suspension drop after setting for some time but if I set it at high before parking it for the night it will still be high in the morning. So I'd have to say no leaks. I have exercised the suspension and does not make a difference. I can raise it to high before driving and it will drop all the way down to low with in about 1 mile and start to beat you to death. But when you stop at a red light for a little time it will start to pump the suspension back up. I was thinking it could be the ride height sensor but after read some of the other treads it does not match to me. It seem like the compressor will not turn on when drive down the road but only when stopped. Is there a sensor on the compressor that gone bad?

This all seems to have started right after I have new tire put on the vehicle. Could they have pull a wire loose or something?

ALAN553

13 years old, there is a pin hole in the air spring. Conventional wisdom....rubber cracks...

Lwalters

I have pumped it up to high before parking it for the night and it did not drop at all after setting for 8 to 10 hours. It will still be high in the morning that tells me no leaks.

ALAN553

The hole opens up when you start to drive and bag adjusts/deflates a bit, fully pumped the hole closes up...been there done it as have hundreds here.

mrblister

You cant drive with the trucks air bags all the way up after a certain speed it automatically lowers it to normal

BradTank

It starts acting erratically when the air bags leak.

Mine would be fine one day and stay at the same height and dropped down the next.

Logically, you would think if something leaked air, it would be consistent, but for a variety of reasons, sometimes the leak happens, and sometimes it doesn't.

Do some more troubleshooting to make sure, but the symptoms you're describing is probably how everyone's started out and if the rear bags are original, I would make a large bet they are the culprit.

I kept ignoring mine as it was so inconsistent, then one day it just dropped and just wouldn't reinflate anymore. Of course I was on a road trip when it happened.

Lwalters

Thanks for the reply, what troubleshooting would you recommend I do. I would have thought that if it was a small air leak the compressor would keep it at least somewhat pumped up as I as I drive down the road. I know if the compressor ran for too long it would automatically shut off but it's like the only time it will run is when you are stopped. For example this morning it was all the way down on the axle when I pulled out of the driveway driving at a low speed and coming to the first stop sign you come to it had already started to Pump It Up to normal. But then when I got on the straightaway for about a block or so it dropped down to the lowest point again. But when I came to the next stop sign it started to pump it back up again.

Lwalters

Yes I know it cannot be driven with the bags pumped all of the way up. But it's like when it but it's like when it lowers it to normal it just keeps right on going down to low.

BradTank

What you're describing to me sounds like a leak in the rear air bags, I would say I'm 99% sure, but I don't like throwing parts at a problem without making sure everything else is working.
Again, mine would be fine one day and the next day really low and then go through that cycle again.

Maybe spray some soapy water on the rear air bags and see if bubbles start forming?

There is additional troubleshooting you can do on things like the sensors, but you'd have to find a service manual to see the steps. Sensor problems are pretty rare though, air bag problems are pretty much the norm with the age of your car.

ALAN553

you can just wait until they totally fail or the compressor burns out from keeping it inflated, then you will,be sure. You can get underneath after hitting the H L N button and listen for the leak while it is deflating. There is a hole there somewhere. It's not like a thin ballon, its thick rubber so the hole will seal when the bags are fully inflated, as the rubber shrinks and creases the hole opens up...it might be just a pin hole or a crack in the rubber. 13 years old....rubber cracks! There is only the compressor and the height sensors other than the bags....clearly it pumps, and when it does it goes to the right height....it's the bags!

Lwalters

Thanks BradTank and ALAN553

Ok from what you two are saying it's the air bags put before I go spend the $$$$ on them. I need to understand something.

How the the height control system works. So I know you can only adjust the height stoped or below 25mph. So does that mean that's the only time the compressor will operate? It will not operate when you are driving down the road?

If if this is correct it would explain why the suspension drops as I drive but the starts to pump back up when I stop.

Also how difficult are the air bags to replace. I am mechanical, I've replace all the struts on my 2002 Avalon.

yackowski

My air bags behaved exactly as you've described at 87k before I replaced them with new Arnott bags. I could air them up and as soon as I hit a few potholes or speed bumps they would deflate and I would bounce off the rear bump stops until I stopped and took the time to re-inflate.

The removal/installation is really straight forward. There is one air line and a flat clip on the top of each bag and the bottom just rests on the axle. The top of the driver side bag is pretty cramped and much easier if you have smallish arms. I would also recommend cutting the air lines really close to the fitting versus trying to remove them from the old bags if you use the Arnott bags.

Cole

ALAN553

height sensors are dynamic, constantly monitoring and adjusting height based upon weight on the rear axel, they are just levers that are attached between body and axle the move up and down, they are adjustable, macro and micro adjustement. the speed limit thing is....if you set the level on H, it will drop back to N when you reach about 19 MPH and conversly if you manually set it to L it will raise to N.

LoneHiker

I think the answer you are looking for is that the compressor SHOULD turn on and try to inflate the bags while you are driving. The sensors are always monitoring the height, so when they sense the height dropping, they will trigger the compressor. So you should be able to get out and hear the compressor running after your height has dropped.If the leak is too much for the compressor to handle while driving, then the airbags won't be able to inflate, but you should still hear the compressor running if you get out and listen for it.

SOTF

OP what was issue? I have a similar problem. If I set my bags to H they stay inflated while parked. It does seem like when I initially drive, they adjust to N and seem to remain inflated UNTIL I slow down below a certain amount (18 mph?). At this point, they deflate within a few minutes and the ride becomes clunky and then bouncy or is it bouncy then clunky. At this point switching it manually from N to L will begin pumping air into the bags as they are deflated . That's what is throwing me off. Why does it remain inflated on the initial move from H to N until the first time I slow below 18 then the deflation starts. It's like it's being triggered to deflate when going under 18 mph even though the icon says N. The compressor does not seem to run while driving unless I come to a stop light and manually hit the switch. Ideas?