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LS430 Air suspension Harsh feeling + 1.5 cm high - error


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Hey guys,

I am really happy with my LS430 but there is a really big problem what keeps me from driving the car for more then 6 months now.

When I start the car, the first few meters or sometimes hundreds of meters its driving fine but then the comfort is gone and its driving horribly harsh. The car lift itself 1.5 cm all around as well. When I shut the car off it resets itself and mostly it will drive fine again the first few meters. 

I have bought 4 new original air struts at the dealer (5000+ euro). I am sure the problem isnt in there. 

I also took the little arm of the hight sensors and I twisted them all up and down and I saw in my IT2 tester that the value went up and down like they suppose to do. 

There are no errors or DTC's. The only thing I found was one "C1752 continuous current to exhaust solenoid" and C1725 Damping force control actuator FR. I must confess that I got those errors after changing the front air struts so I am not sure if this has anything to do with it.

The only part I havent checked is that exhaust solenoid. I have found out that there are 2 of them. One under the car near the differential for the rear wheels and one for the front wheels and its located near the compressor at the front right wheel. Since they are 500 euro's each I really dont want to change them just by guessing. Its just to expensive to play around with such numbers and I am not even sure if this will solve the problem. 

I really hope someone over here can help me out since I have a deadline soon and I really need that car. 

Thanks in advance for your help and thoughts on this. 

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I don't know much about the 430 but, on my 460, I can get those symptoms if I select the suspension to 'HEIGHT HIGH' and 'SPORT'. It takes a few seconds for the compressor to kick in which could be the reason you get a few metres of normal driving.

This wouldn't show up on your meter as a fault, because it isn't.......it is a normal function of the car. Now, if this is happening because you haven't selected anything, you do have a problem.

There is an old engineering saying: If things don't go back to normal after you've done some work, then you and the work are the problem. It could be that there was an error made when the struts were changed.

Best of luck.

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What was the original fault before you replaced the air struts, the same as you have now or something different and how did you diagnose it was the struts initially?

Toyota Techstream is the standard diagnostic system which may allow live testing of the suspect valves.

Even given what you have already spent on struts a coilover replacement kit may still work out the cheaper option as many members have already done.

 

 

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1 hour ago, Tulpen said:

I don't know much about the 430 but, on my 460, I can get those symptoms if I select the suspension to 'HEIGHT HIGH' and 'SPORT'. It takes a few seconds for the compressor to kick in which could be the reason you get a few metres of normal driving.

This wouldn't show up on your meter as a fault, because it isn't.......it is a normal function of the car. Now, if this is happening because you haven't selected anything, you do have a problem.

There is an old engineering saying: If things don't go back to normal after you've done some work, then you and the work are the problem. It could be that there was an error made when the struts were changed.

Best of luck.

The problem was already there before I changed the struts 😞

I like the saying though! 

I was planning to buy an 460 2007 next to the 430 but after reading about brake actuators failing, steering racks (5000+ euro) failing, and suspension bushings failing I got scarred. There are even stories about dangerous driving situations with braking and steering and thats scares me even more. 

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36 minutes ago, steve2006 said:

What was the original fault before you replaced the air struts, the same as you have now or something different and how did you diagnose it was the struts initially?

Toyota Techstream is the standard diagnostic system which may allow live testing of the suspect valves.

Even given what you have already spent on struts a coilover replacement kit may still work out the cheaper option as many members have already done.

 

 

I accidentely deleted the fault the first time and it never came back. With the IT2 tester I cant check the history of faults... I was hoping with deleting the fault the car would drive perfect again.... Most stupid mistake I could make.... 

Anyway. Those other errors came back with the valve... I just dont know what exact valve because there are 2 of them... I have techstream on a disk. I am going to try to  hook up my laptop and test it myself. 

 

 

 

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  • 3 weeks later...

There's actually only one exhaust solenoid on the system, at the front. Off the top of my head it's next to the pair of solenoids for distribution. I can't remember if it's its own part or bundled as part of the distribution solenoids, think it has a simple 2-wire connector. At the rear of the vehicle is another pair of DISTRIBUTION solenoids (packaged as a single part) that control the rear left/right distribution. If the car need to vent air out of the rear, it opens the distribution solenoid for the appropriate rear side, and the air returns up the single air line back to front where it escapes from the front exhaust solenoid. The car can vent any corner using a clever combination of shutting the other three corners and opening one corner while simultaneously opening the only exhaust solenoid. 

So if you genuinely do have an exhaust solenoid problem, it's at the front. 

That being said, if the system is seeing correct heights all round then it should not need to add any more air or vent it, so I would wonder whether your problem is actually incorrectly adjusted height sensors, especially as you have stated that you have messed with them. They should all have their arms flat (horizontal) when the car is on level ground and the car is "happy" with its height. That assumes "High" is not selected on dashboard.

If your parking spot is on a slope or very uneven then it's theoretically possible that the car tries to compensate for a weird weight distribution there and add air to try and level the car, then when you pull away onto level ground it realises it has too much air and need to drop but can't because of a faulty exhaust valve I guess. However, definitely check the sensor arms are horizontal first, as that's a simple visual check you can do in any flat place which can be interpreted to tell you where to check next before you make another expensive purchase that doesn't help.

If an arm points upwards, that corner is low and the car should be trying to pump it up. If pointing downwards, that corner is high and the car should try and vent (unless it physically can't drop any more due to poor rod adjustment). If flat, car should be happy (even if rods are maladjusted, that's outside the scope).

Finally, you mentioned"C1725 Damping force control actuator" as well. The actuator is the little black stepper motor that twists onto the top of each strut when you install them, they control the damper of the strut, and twist a little motor inside when you select "Sport" mode. They're not usually problematic, so check you have twisted it back on properly and remembered to reattach the wiring for it.

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  • 4 weeks later...

Hi Peter, thanks for your reply!

The C1725 are mounted correctly. I was very precise with that. How many times do they twist do you think when the sport mode is active? I talked to an air strut specialist and he thinks its maximum half of a turn and not more... I did some research on that because the car is harsh and that could be because of the dampening and I thought the problem could be over there....

Ill check the arms asap! 

Since the fist day I own this car I see strange behaviour. When I come home and I let the car idle for a few seconds the car lift itself on the driver side and lower itself on the passenger side (front and rear).

I unbolted the rear sensors (which are both tuned in the mostly down position) and bolted them back onto the car on the very exact spot and now my car is raised on both sides in the rear for a minimum of 5mm. And exactly the same on both sides... I absolutely mounted those sensors back at exact the same point on the car. Since I have coated parts in black I can see the exact stamp where they use to be. 

 

 

Schermafbeelding 2022-05-27 om 11.09.14.png

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I believe you can do active tests on the damper motors, try this in Techstream, I believe they can be actively moved to more than ten positions. Your readings for the rear two sensors do seem odd! Are they set in the middle of the slot, and also have you measured your front two sensor arms to ensure they match left and right? Should be 92mm inside nuts from factory up front.

You're mentioning a 5mm difference, not sure what part you mean for that? If that's the only difference at arch height, that's not much at all!

I'll also put a picture of some values from mine today. The car was on Normal height setting, on flat ground with the tiniest of slopes to one side (barely noticeable). You can see the car did not try and get 0mm measurements, it adjusted the front L to R slightly to adjust for the tiny slope. On the back, they are almost identical, but you can see they are not zero. I do not know why, but clearly the car has decided this is best. From outside I felt all the gaps between the arch and wheel and they were all perfectly the same, so even though they are not 0mm, the car made good choices. Don't try and chase perfect zeros! As long as L and R are in broad agreement, the sensors are probably fine.

 

PXL_20220527_122432002~2.jpg

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