GadgetRick

2003 GX with 150k miles on it. Left this morning and felt a super rough ride in the back and it was leaning back a bit. Suspension in the rear wasn't working for sure. Stopped eventually to go in somewhere and, when I cam out and restarted the truck, suspension was fine. Was good all day until I was on my way home from picking our son up from a party. Halfway home, ride got rougher and rougher (assuming the bags were deflating). Pulled into the garage and restarted to see if it would fix it again. Sure enough, heard the pump kick in to inflate again.

Not sure if it's the ECU (or whatever it is, which controls it), the pump or something else. What can I do to troubleshoot this?

Thanks.

ALAN553

12 years old, I would be looking for a leak in those air springs.

GadgetRick

It's not a leak, it's a problem with the system. For some reason it's intermittently failing.

roemer7

My '06 was doing something similar. Every other day or so I'd have to raise the back end because I'd be hitting the bump stops while driving around town. It had also stopped self-leveling after I parked the car. It wouldn't release air from the system once parked like it used to.

I thought I'd try to do the airbag trick and raise the back end a little and see what that would do. I got out my impact wrench and broke the bolts loose on the drive height sensor. I installed the washers and successfully raised the back end by an inch or so. But guess what? I also fixed the leakiness of my airbags and it now releases air and relevels itself again after I've parked. I think banging around on the ride height sensors with the impact wrench and working both of those switched really good somehow fixed my problem. You might want to try that.

ALAN553

The leak is intermittent because the hole in the air bag opens up only when the bladder is deflated just enough to allow the pin hole to open. That or the solenoid reservoir or the height sensors, or all three. The age of the truck, it's not a matter of which, but when.

GadgetRick

I totally understand the age/mileage issue. I expect things to stop working/need replacing. What I'm saying is, if it were just a leak, the pump would still try and inflate the bags, when these symptoms occur, the pump won't even attempt to inflate the bags. So, my guess, is it's maybe something else like the height sensors or something like that. I just don't know how to go about troubleshooting it.

GadgetRick

Interesting, do you have a link or more information on how to do all of this? I don't have an impact wrench or anything but the guy who does all of my work knows toyotas inside and out--was a tech at a dealership for many years--and I'm sure I could explain it to him.

Thanks.

dkotanto

If there's a leak, the pump will eventually stop running after a predetermined amount of time to protect itself. When you first start the car, the pump will kick in to inflate the bags but if there's a leak, it will stop running causing the leaky bag(s) to deflate thus creating the harsh ride.

ALAN553

Like he said, it's most likely the air bags, the solenoid reservoir or both.

GadgetRick

How do I troubleshoot to figure out what the problem is? I can't find anything online about how to troubleshoot the system.

ALAN553

You can get under the truck raise and lower the height, see if you can hear a leak/hiss at any point. Trip to the dealer for error codes?

GadgetRick

I've heard a hiss so it could be a leak on the right side. It's not throwing any codes or I'd read them myself. I still think it's more than just a leak but, honestly, I know very little about this system, which is why I'm asking questions like I know nothing because, well, I don't. LOL!

ALAN553

If you hear a hiss....its a leak...I have a 2004 with 157K miles...been down this road. Replaced it all or you can do the coil spring conversion mentioned in many posts here. are you attempting to figure it out yourself because you are going to do the job yourself?

GadgetRick

Not doing it myself, just want to know what needs to be replaced. The guy I deal with is extremely reasonable for labor and will use parts I get.

When you said you replaced it all, you mean the whole system or went with coil overs? Considering this but wondering if it's really worth it to do that. I do plan on keeping this thing for quite some time and trying to take care of it.

ALAN553

Lexus replaced reservoir and air bags, I did the sensors myself afterwords, just to make sure. I have no plans to get rid of the truck so I went for it. In hindsight maybe I should have gone with the coil springs..,maybe at 300 K, ha just had lunch with a friend that has a 2003 land cruiser, 350K. Only thing that has been replaced other than scheduled stuff has been a fuel pump. Going in tomorrow for full trans flush....I am committed.