Air Suspension weirdness after garage visit

[NickJrv]

Hi,

I've searched all over for what I'm experiencing and can't find it. Most posts relate to struts losing height and needing replacement or a left/right side imbalance. Mine is rear vs front imbalance. All 4 struts were replaced in past 3 months, so I'm sure they are fine.

So... I had the car in the garage today. After being on the ramp, my mechanic (independent garage) tried to set the heights at each corner to Lexus-recommended heights. It took the changes. The rears were even. The fronts within a cm of each other... but... when the car was restarted the fronts went high (maximum height it looks like) and the rears v low, almost the low setting.

Now, it had been on the ramp so the dampers may have needed to settle, but it's weird.

The only lights that the height button will go to is H and N. It doesn't flash when I move between the two and the height doesn't adjust at all. It won't go to L at all. The fronts strut basically seem to be stuck on H and the rears on L.

Do I just need to be patient, let the dampers settle and hope it sorts itself out in a day or two?

I tried disconnecting the Battery. No change.

I tried manipulating the height sensor arm to let the air out so all corners were on the L position. Disconnected the Battery. Waited 30 mins. Re-connected, turn on car, pump came on, raised only the front to max height and no height at rear.

N.B. all 4 struts are new (within 3 months old)

Is there a nice reset trick I can do?

[JasonH]

I think you need some diagnostics. I'd suspect the height sensors or wiring. Either there will be some fault codes logged or viewing live data from the sensors should reveal what is going on.

I very much doubt it will settle itself.

What I have seen on (a BMW) is after fitting new air struts a garage didn't connect the height sensor arm. The car always thought the suspension was low and inflated the strut to maximum.

 

[NickJrv]

@JasonH Thanks... worried that might have been the case 🙂

What's really odd is there are absolutely no error codes at all 🤔

[NickJrv]

Okay, for anyone who ends up with a similar scenario... I adjusted the front sensor 'arms', which can screw in or out to shorten or lengthen the rod. This has the effect of moving the position of the sensor internals, depending whether you want more or less air in the struts. I wanted less air (in the 'N' position) so I shortened the rod gradually till the suspension dropped.

This also had the effect of "un-disconbobulating" (does that word exist?) the suspension set-up. I was then able to select H, N or L and hear the compressor doing its thing. It's not perfect, but the ride looks much more normal at the front, the rear struts went up about 5-10mm which gives it 'some' dampening in the aft... the car is at least driveable now 👍

I have tried to lengthen the rear adjuster arms a couple of mm to see if that pushes the rear struts up a bit more. Didn't seem to make much difference. I may just need to do a couple more mm, but don't really want to push it as that may not be the issue at the back - could just need a clean up of the sensor internals.

I'll update this thread with any more news 🙂

[JasonH]

Again from experience with a BMW, there's a height calibration procedure in the diagnostics. Here you measure the heights at each side and enter them, the car does the maths and corrects itself.

I wonder if the garage has misread the instructions and done this incorrectly. You don't enter the desired correct values, you enter the actual (incorrect) values which can seem a little odd.

[RONNIE W HODGEKINSON]

On 10/26/2023 at 7:04 PM, NickJrv said:

Hi,

I've searched all over for what I'm experiencing and can't find it. Most posts relate to struts losing height and needing replacement or a left/right side imbalance. Mine is rear vs front imbalance. All 4 struts were replaced in past 3 months, so I'm sure they are fine.

So... I had the car in the garage today. After being on the ramp, my mechanic (independent garage) tried to set the heights at each corner to Lexus-recommended heights. It took the changes. The rears were even. The fronts within a cm of each other... but... when the car was restarted the fronts went high (maximum height it looks like) and the rears v low, almost the low setting.

Now, it had been on the ramp so the dampers may have needed to settle, but it's weird.

The only lights that the height button will go to is H and N. It doesn't flash when I move between the two and the height doesn't adjust at all. It won't go to L at all. The fronts strut basically seem to be stuck on H and the rears on L.

Do I just need to be patient, let the dampers settle and hope it sorts itself out in a day or two?

I tried disconnecting the battery. No change.

I tried manipulating the height sensor arm to let the air out so all corners were on the L position. Disconnected the battery. Waited 30 mins. Re-connected, turn on car, pump came on, raised only the front to max height and no height at rear.

N.B. all 4 struts are new (within 3 months old)

Is there a nice reset trick I can do?

Its Just Possible That if you had taken the car to a Lexus Dealership to Fix You Would,nt have had this problem Glad you got it sorted..!!!

[NickJrv]

@RONNIE W HODGEKINSON My problem was I couldn't drive it anywhere! 🙂

But I can now, so Lexus may well be my next step 👍

[Spock66]

Now you know what the problem was and have a working fix, may be worth checking the service manuals if there is any calibration process you need to go through.

[NickJrv]

Thanks @Spock66 I think that's where Lexus will come in... not taking any chances now 👍

[NickJrv]

On 11/2/2023 at 8:36 AM, JasonH said:

Again from experience with a BMW, there's a height calibration procedure in the diagnostics. Here you measure the heights at each side and enter them, the car does the maths and corrects itself.

I wonder if the garage has misread the instructions and done this incorrectly. You don't enter the desired correct values, you enter the actual (incorrect) values which can seem a little odd.

I've just re-read this (after a good night's sleep!) and may get this checked. Good thinking - thanks