RX300 Suspension problems

[GeoffBrown]

Suspension problems with RX300 (SE-L 2004):

I've had the car about 6 months and have noticed that each wheel seems to select it's own height setting! I started looking at the problem seriously when my wife complained that sitting in the back seat had nearly broken her back and she described the ride like "sitting on a park bench".

I went out this morning after the car had been sat there all night and took measurements from the centre of each wheel to the wheel arch in the 'cold', Hi, N and Low suspension height settings. They are all over the place.

----------Front L - Front R - Rear L - Rear R

Cold-- 45.5-------50.0-------41.0------45.5

Hi-------51.0-------51.0------52.0-------50.5

N-------47.0-------48.5-------44.0------44.0

Lo-----45.0-------47.0-------42.0------43.0

Measurements are in Cm. So you can see, when the engine's cold, I've got a 9cm difference between 2 of the wheels, and when running in 'N' I've got 4.5cm difference. I'd better point out that I didn't drive the car in-between changing the height settings. So my problem seems complicated and I'm not sure where to start! I've run an OBD check and don't have any faults listed on the ECR. The compressor runs ok and I can't hear any obvious air leaks.

I did come across a post which I've been unable to re-locate which mentions an on-board test monitor which can be activated by turning the side lights on and off between 6 and 12 times and when activated, will show suspension problems?

Any sensible suggestions gratefully accepted but I'm not rich so would rather keep clear of a Lexus garage! TIA

P.S. I'm in the UK

[GeoffBrown]

Or... 

If anyone can tell me how to access the suspension codes, that'd be a great help!

[sorcerer]

If you have a laptop or have access to one, a miniVCI Cable from eBay will come with a copy of Techstream, which I would imagine should be more helpful at diagnosing this particular problem rather than just a generic OBD2 reader.

[GeoffBrown]

Thanks for the advice - I'll give it a go!

Update; Now ordered!

[GeoffBrown]

Ok, here's a good one! Hopefully, some bright spark on here can enlighten me as to what's wrong?

I've got the software now but before I load it onto my laptop, I just thought I'd disconnect the Battery for 30 minutes as has been suggested elsewhere, in order to 'zero' the suspension memory. I re-connected the Battery after 30 minutes and then selected 'L' on the suspension height control followed by 'N'. Lo and behold, all 4 wheels ended up at the same height! Yippee!

However, I then took it for a 5 mile spin. After I parked in my drive and selected park, the suspension compressor kicked in and raised only the right hand side of the car up! The easy access was not selected at the time. Can anyone tell me which unit's not working properly or should I attempt to find out via Techstream when I get it up and running?

[GeoffBrown]

Update:

OK, so the car was low on the left-hand side and that's all been sorted out via Techstream which I managed, after no small amount of floundering, to get to work for me.

However, in the 'N' position, the car's now straight and level but if I change it to Hi, I've got 2" difference between corners. Can you make similar corrections via Techstream when in the 'H' mode which will only effect the high mode of operation? Failing that; help!

[The-Acre]

50 minutes ago, GeoffBrown said:

Update:

OK, so the car was low on the left-hand side and that's all been sorted out via Techstream which I managed, after no small amount of floundering, to get to work for me.

However, in the 'N' position, the car's now straight and level but if I change it to Hi, I've got 2" difference between corners. Can you make similar corrections via Techstream when in the 'H' mode which will only effect the high mode of operation? Failing that; help!

I'm glad you've got somewhere with this.  I've got Techstream but so far I haven't managed to get it to work!  I really don't know re your question but my immediate thought would be don't put it in H! 

[GeoffBrown]

I don't intend to and don't really need to. It's just that niggling thing in the back of your head that keeps telling you that something's still wrong!

Not sure if your Techstream explorations are in search of air suspension adjustment, but if they are, here's something borrowed from a sister site which helped me a lot:

 

This has taken a few weeks to get right, but I think I have it.

What you need:

Techstream 10.whatever is the common one

A cable, which is USB to OBDII (the above come as a set on eBay for under $20)

A laptop (as long as it's a Windows OS, XP or later, it doesn't matter...I run it on 64-bit Win 10 machine, no VM, no dual boot, nothing special)

Patience

Some gasoline in the tank

A notepad if you don't want to take notes on the laptop (paper and pencil may be easier, in fact)


Fire up your TS and connect it to your running LS. Double-click Air suspension Live. Give it a while to figure things out...

Eventually, you'll be able to go over on the left side of the screen and select Data List. There's going to be a bunch of stuff in there you don't care about, so at the bottom of this window, see the field with the drop-down arrow, the one to the left of the graph button? Yeah, that one. Hit the drop-down and choose Only Suspension Height.



Now you have only the fields "after height adjustment" and "height adjustment".

The corners are labeled FL for Front Left, RL for Rear Left, FR for Front Right. RR is the only one which looks normal.

Take a freakin' screen-shot of this before you change one damned thing! I didn't, and regret it. I have no idea where I started, but would really like to so I have a better reference. In fact, if a few of y'all could PM me a screen shot of your un-modded height at 'normal' ride height, I'd really appreciate it. I think my first foray into the suspension was lowering one inch, just to see how things may change.

Oh, there's also "Height Offset Max" as a field, but what I did was use that one as a separating field with "After Adjust" above and "Height adjust" below it. I haven't figured out how to put them on the same line, left and right, but I found it's easier to track changes if they're in the same order. Height Offset is how far the car will rise when you push the Height High button. I wish it were more like 2 of travel available, but Ill take what I can get.

Im one of the very few who uses Height High daily, because its easier for my crippled self to get in/out. That 0.8 makes a very noticeable difference. This is even more true since Ive dropped it a bit.

Be aware...changing the left front, or the front left in this case, WILL change the right front and probably the left rear a little. Might even change the right rear if it's a large change.

The first two times I did this, I measured from the floor of my garage to the edge of the wheel well, going through the center of the wheel. This way every corner is measured identically. You'll very likely find if you measure with a yardstick or the like, yours may have two matching corners...if you're lucky. I had none.

In playing with heights, I found that, for freeway travel, because the air suspension lowers at speed, I couldn't dial it in as low as I wanted. Once on the freeway, I'm pretty certain I feel the bump stops and the ride was choppy (though still not at all 'bad'). It's been 25+ years since I owned a lowered vehicle, and even then I did bump stop trimming so as to have as much travel as I could, so I'm a little rusty on what feel is what.

This is where I'll save y'all a ton of time. A ton of it.

Now, instead of measuring every corner every time you adjust one, use the TS to bleed all the air out of each spring. Select Active Test, and a new window will appear. Double-click one corner of the car, let's say RL, and you'll see yet another, smaller window appear at the bottom-right. It'll say, for example, RL wheelup/down (S307-24). There will be "OFF" and a left and right 'button'. Pressing and holding those buttons either releases air, the left one, while the other adds air, the right one. When the solenoids or compressor are doing something, the OFF becomes ON.

In the main screen behind where the button is, you'll see the data readout. Choose the left or "down" arrow and watch the real-time data stream. See how it's dropping? -0.3, -0.7, -1.3...eventually you should get to around -1.6. Might be -1.9...every car should be different, but just a little.

Get out and just look at where that left rear tire is sitting in the wheel well. Awwwwwww, yeah, buddy!

Repeat letting air out of the springs until your numbers on the TS stop dropping. You should see the front has much more travel than the rear...like an inch or more, more. I think this is why some people, including me, see the LS460 and think it looks low in the rear. It's because the front rides a little higher.

After you lower every corner, go around them, again, and press the down button for 15 seconds and see if you get any closer to the ground via the TSs data readout. Might be only a couple tenths of an inch, or a few MM, but you need to have everything bottomed-out for this to work.

Just to have it, Id go around an measure the height at every corner. I found, when bottomed-out, there was still a variance, which is important, or youll never finish.

Here are the actual measurements on my 2008 L (attached picture).

Please note, even with seemingly no air in any springI went corner-to-corner, around the car, twice, and held the bleed arrow for 30 seconds on each corner, just in case, but nothing happened after the first time I went around it. Its as if air can move around a little in this system. Not much, a couple tenths of an inch in height here and there, but it all adds up.

If you look at current normal, thats normal ride height after me playing with it a little. You can see, I managed to get it mostly level, though the rear behaves strangely when changing pressure (hence, height). Sometimes youll get a huge change in the RR when youre working on the LR. Small changes in any other ones are to be expected, but the large swings are frustrating to work around.



We, however, are interested in the bottomed-out number. In this case, about 25.75, with two outliers. We can deal with them, later, if need be.

As she sits, my car has 2 of compression suspension travel before she hits the bump-stops. I learned this is about 1/2 too little for 70 MPH (posted) freeways here in Fort Worth, Texas. I went, after my first adjustment last week, from about a 1-1.5 drop to an even 2, and that was about ¼ too much, maybe the full ½.

So today, I went out to my car, laptop under my arm, and what I did this time was re-bottom it out, then from there, did some minor maths to bring the whole vehicle up 2.25 from as low as it goes. I guess I cant see 3/8 when eyeballing the tire-to-fender clearance, cause they all look to be the same distance. I also tweaked the front height to be more in-line with what the rear looks like, because to my eyes, every LS460looks like it has a couple of bags of concrete in the trunk.

Back to getting it mobile

Lean your drivers seat back, back, get in, put the laptop on your lap, engine running, and make quick notes about how much air to put back into each corner so theyre all at about 28-28.25.

At this point, in Techstream, choose Active Test again, but this time add air and watch the numbers on Height Adjust change. What youre shooting for is X added to the bottomed-out number.

So, if you want 3 of travel because your roads suck, on my car, Id have to put air into the LR spring until it read about 1.3 higher than it is, now.

When adding or removing air, I suggest you stop a couple-few tenths of an inch from what you want the final reading to be, until youre on the last spring, because changing the pressure to any of them lessens the load on the rest, so the whole car moves a bit.

I may add to or change this, depending on what I find or remember.


 

  

[The-Acre]

It wasn't actually for anything in particular, just something for the future should the need arise. 

[GeoffBrown]

Is there an RX300 SE-L owner out there who could let me know the measurement between the centre of the wheel hubs to the wheel arch for the front and back wheels when the suspension is set to 'N' PLEASE? I'm attempting to tweek my suspension but don't know what height it should be at in the first place.

[Herbie]

Not sure if this will help but it shows a 'Standard Value Table' (although it's not as easy as measuring centre of hubs to wheel arch):

[GeoffBrown]

Thanks Herbie, I'll take a closer look using your notes!

[Herbie]

You're welcome Geoff, I like to help when I can  😊

[GeoffBrown]

Well, my problem's finally cured. I took it to Lexus in Lincoln. The rear NS height sensor, which I'd previously had straightened and welded, had come away from the car. They fitted a new height sensor (the old one had also frozen completely). They also reset all of the suspension heights back to the original settings. Now drives like a dream and the suspension works as it should - apart from a wheezing/graunching noise coming from the front NS suspension arm - or somewhere around the wheel strut. This only occurred after they'd carried out the work. I'm taking it back to them this next week for them to take a look at. Total cost to date for peace of mind: £777.

[NickJrv]

On 10/27/2018 at 8:14 PM, Herbie said:

Not sure if this will help but it shows a 'Standard Value Table' (although it's not as easy as measuring centre of hubs to wheel arch):

@Herbie Bit of a 'bump' 5 years on... but do you have a copy of teh full file that you took this screenshot from? If not, do you know where I can get hold of it? I could do with some diagnostic help... 🙂

[Herbie]

2 hours ago, NickJrv said:

@Herbie Bit of a 'bump' 5 years on... but do you have a copy of teh full file that you took this screenshot from? If not, do you know where I can get hold of it? I could do with some diagnostic help... 🙂

Just sent you a PM Nick, hope it helps.

[NickJrv]

Thanks 👍 

Really appreciate it