tzh2231

Guys I remember seen plenty discussion on how the air suspension system can go bad and give you a bouncy ride, now finally I got my turn

Here is my symptom:
1. When I ride through even a minor bump/hole on the road, rear half of the GX470 will get as happy as a puppy, jumps up and down a few times before settle down.
2. My height control seems to work only one-way to high. When going from N to high, I hear compressor kick in, and both sides actually do rise a couple of inches. However if I then switch from high to N or low, it seems to just blink green and do nothing. I did not wait very long, so not sure whether it is just delay or not working.

Since N->high works, I assume my pump and sensors and air bags are all good? Looks like the issue is the pressure cannot be released or at least not in a timely fashion.
So what is the next step? What is the part that is in charge of release pressure?

ALAN553

tzh2231

ALAN553

the weakest and most vulnerable link in this rear suspension is the air bags...if there is a slow leak and the compressor is running overtime it will confuse the system and you will get symptoms that are sporadic and hard to explain....until the truck just bottoms out and stays there becasue the compressor has blown from overuse.

IanB2

Bouncing up and down after a bump is an indicator the rear shocks are blown, have a look for leaked oil at the bottoms of them. While you're under there, have a look at where the bumpstops contact the axle tube, if it's riding too low or too soft due to worn out airbags there will be a clear indicator of regular contact at this point, which isn't right.

tzh2231

IanB2

The shocks should be pretty easy to identify, the bump stops I'm referencing are at the ends of the axle just inboard of the brakes, they are big rubber blocks that limit the axle's uptravel.

tzh2231

chiph9

The bump-stops are around $40-45 each. More than you'd expect for blocks of rubber, but so far as rear suspension parts on the GX go .. pretty reasonable.

Agree that you should check for air leaks on the bags. One test you can do is get four adult friends and have them all get into the GX at the same time. Listen for the compressor at the driver's side rear. It should come on for about 20-30 seconds to re-level the vehicle then shut off. Wait about 2-3 minutes to see if it comes on again (it shouldn't). Ask your friends to step out. You should then hear the valve open and release air from the bags to lower the GX back to level, again in about 20 seconds. If you hear the pump cycle on/off, that tells you you have a leak and you don't want to delay getting it fixed - if you burn out the pump a $500 repair goes to $1200+.

Something that wasn't mentioned was the height sensors. They tell the computer when the GX is too high/too low, and to run the pump or open the valve. Since you live in MA, which gets lots of rust, it's common for the arms on the sensors to corrode. If you're ok with cheap Chinese knock-offs, they're in the $50 range. Lexus OEM will be around $350 each.

Chip H.

mrblister

This link is for bump stops made by timbren I used them on my 2004 gx470 I jus bought the rears did not think I needed the fronts


https://www.truckspring.com/helper-s...04&model=GX470

btreiber

I have the same problem, however when I went to re-calibrate the height control (engine running raise to high wait for the green light to stop blinking the go to low and wait for the light to stop blinking). I did this twice and the light got stuck in high. I could hear the compressor run and I also noticed the rear passenger air bag wasn't raising at first, then it released with bump like noise. This happened a couple of times when going up and on the way down. It seems to be sticking. If I turn off the car then I can move the height control again. After raising the vehicle I can drive it and it rides fine however after a while it get real bouncy again. It will continue to bounce severe until I put the height control to High and then N before I drive. After reading the posts I believe the Air Bags will need to be replaced however I want to see what other say about this. I appreciate any thoughts on this problem.

tzh2231

Hmm sounds exactly like my symptom, but I am a little unsure about the bag needs replacement. It could be the sensor? Anyway this should be resolved by installing the conversion kit.
I am planning to do so when I get some time. My other choice is to trade it in for a new one, still debating.

Gfat87

could easily be a ride height sensor as well, have you tried fiddling with that and changing the height of the sensor?

i got 2 bags and 2 rideheight sensors if anyone is needing to purchase. 100$ plus shipping.
ripped mine out as i put in a lift.

i also have the electronic shock i suppose. haha

Lexus4321

If the bags are bad the pump will continually try to pump.
If the pump is bad, the bags will go flat at some point and not pump up, but you can hear the pump go if it kicks on. Pumps can die.
Height sensor is not likely to go out of adjustment, they can go bad.
If you put height control to H and dont hear the pump, I would look at the pump.

Bad shocks wont affect the ride height, the height is all bags, etc.

Make sure the Air fuse is not blown.

ALAN553

airbags are the weakest link in the rear suspension....if there is a leak and you don't catch it soon enough...the pump will burn out from over use...so when that suspension starts to slouch....look at those vulnerable rubber airbags...shocks don't contol ride height, just ride quality....height sensors can rust out but not usually the most likely cause...