BSarles

Ok, my 470 has 185k and I'm getting no codes from my control systems. I live in Florida and when we either go on I-4 or over speed bumps or groups of holes / very rough road whear the suspension has to see some mild action the compressor kick on and can't keep up and then shuts off leaving it stuck in the N position and the kiddos are bouncing like ping pong ***** in the back. I have done a leak down test and nothing found. I reset the system and off we go like a magic carpet ride until we hit roads where is gets bumpy and the compressor can't keep up.

I have read a bunch of stuff about sensors and so on... truck is level and after a reset I get my ability to adjust the ride height again.

so in my engineering mind I'm thinking it's a worn out compressor?

any other advice please advise.

Thnx.

ALAN553

If your reading all the posts here, you must know that the air bags are made of rubber, inflate, deflate every day, over and over for 185 k....they dry and crack and leak....

IanB2

The compressor pumps up the bags to ride height (as dictated by the rear sensors) when you 1st start the truck, or if you add load to it at some point while running, and that's it. If it's having to run again while the truck is in motion and the load hasn't changed, the air is getting out of the bags.

Air suspension parts are expensive, and you never know when the next expensive component will go. Rear spring conversions are comparatively cheap, and should last the rest of the vehicle's life. You have a decision to make.

oardila99

BlackCat81

oardila99

I6turbo

iTrader: (1)

Another thing to consider is that the suspension travel on the rear is very short, relatively speaking. Take a look at how little travel you have between the rear bump stops and the axle; it's very minimal, and IMO, something that Toyota should have done a little differently on the GX platform.

From your description, I'm not at all sure there is anything wrong with your air system. You may just be hitting bumps that are severe enough that the suspension travel needs to be more than the very few inches that are available at normal ride height.

Also, have your rear shocks ever been replaced?

oardila99

Absolutely not. Nothing in the above reply makes any sense. l6turbo, have you ever had a GX, and has this happened to it? With all due respect none of what you stated makes any sense:
1. "Another thing to consider is that the suspension travel on the rear is very short" - it's not too short. Its adequte and if this starts happening to a 2005 truck that means that its a new problem that developed.
2. "I'm not at all sure that there is anything wrong with your air system" - wrong. If truck starts to bottom out when parked, it's leaking air from rear suspension.
3. "You may just be hitting bumps that are severe enough that the suspension travel needs to be more" - come on man.. really? the man knows his car, and he knows ride is unsusually rough over small bumps. I own a GX myself, and for bumps to be severe enough to to hit the end of travel of the suspension... the truck would come apart first. it just doesn't happen.
4. "have your rear shocks ever been replaced?" - they have nothing to do with truck bottoming out.

So man, its most likely the air springs. Just need to get down there and spray some soapy water on the whole system while cycling and finding the holes. The air springs are easy to replace. I just did mine 2 weeks ago. See other thread on this.

ALAN553

Kris9884

iTrader: (7)

I love all of the mysterious periods in the title, as if this situation is a huge mystery.......................... Search bro

Luap

I hear my air pump come on sometimes , like today , stopped at store and walking by the rear I heard the pump , engine still on .
Is there a reason it would come on at that time ?

New air bags less than 2 years a go by previous owner , too

ALAN553

I6turbo

iTrader: (1)

Yes, I have a GX that I've had since 2005. It's one of 46 vehicles I've owned in my life. On these I've done all of my own maintenance and repairs, all my modifications, engine building, chassis building, along with pulling wrenches on numerous other vehicles and heavy equipment over the years. Other than tire mounting and balancing, I've probably paid for repair or maintenance services less than 5 times in my life, starting at 13 years old when I started driving and modifying vehicles. My GX at 140K+ miles had one of the rear air bags develop a slow leak that I addressed. And as is frequently reported by other GX owners, mine bottoms out over speed bumps and bad dips in the road. The truck is widely known to have limited rear suspension travel at the normal height setting which is where the system runs when on the road at speed.

Here's a GX sitting at normal height.


Here's the suspension travel between the axle housing and the bump stop on the above vehicle:

The clearance is 40.5mm, aka 1.6" of suspension travel. That might be plenty to you, but it's what I call "very short," and will absolutely cause what the OP was describing when going on speed bumps or very rough road.

Where did anyone say the truck was bottoming out when parked? The OP wrote, "...when we either go on I-4 or over speed bumps or groups of holes / very rough road whear the suspension has to see some mild action the compressor kick on and can't keep up and then shuts off leaving it stuck in the N position and the kiddos are bouncing like ping pong ***** in the back. I have done a leak down test and nothing found. I reset the system and off we go like a magic carpet ride until we hit roads where is gets bumpy and the compressor can't keep up. All of that could suggest no issue with the air bags, but the suspension is bottoming out on the bump stops. That's why I said "I'm not at all sure there is anything wrong with your air system."

The truck would come apart if it hits the bump stops? Nonsense. You are reading a lot into the OP's message that isn't there. He is assuming the "compressor can't keep up" but there's no compelling evidence in his message that there's anything wrong with the compressor or the air bags.

Assuming that you realize that the OP was talking about rough RIDE, not the vehicle slumping in the driveway, you appear to be clueless about what shocks do. If you have less than 2" of suspension travel, your only hope for reducing jounce and therefore bump stop contact when you hit a severe bump is to have a good, not-worn-out shock absorber that damps the movement before it reaches the limit of travel.

He said he did a leak-down test and found nothing.

Dredmond

Did you ever get this issue fixed? Was it the compressor or the bags or sensors?


Similar situation.