restor2

I have an 06 LS430 UL with about 30k miles which has had its air suspension replaced with the sport suspension. All components were replaced including the struts and the roll bar.

At low speed, there is a solenoid type noise coming from what seems like the trunk area. I am assuming that this is an air suspension solenoid that is going on and off, but do not know for sure if that is the case or what to do to get rid of this noise.

The 40A (green) fuse for the air system compressor that is near the battery was removed during the conversion, but no other fuses were removed. There are no lights on on the dash. There is no noise from the suspension going over bumps or driving at speed, or any other noises from the car at speed.

Can anyone advise what needs to be disconnected to get this air suspension solenoid to stop flipping on and off (if that is in fact what it is)? It only happens at low speed, when starting to move or going into reverse. It does not occur as a result of putting the foot on the brake, and the noise is not coming from the brakes. It can occur without putting the foot on the brake, and it does not happen immediately after starting to move the car. It will happen a few seconds after the car starts to move forward or in reverse.

It sounds almost like the trunk is latching and unlatching. I had a mechanic sit in the back of the car and he said "there is a solenoid from the air suspension that is making that noise."

Thanks in advance for any help.

tiger02

I had the same noise when I test drove mine after replacing with coil springs. I disconnected them and no issues since. I also only removed the fuse that was near the battery.

Lavrishevo

iTrader: (1)

You guys did not kill power to the compressor at the swap?

restor2

Thanks for your response.

What else did you disconnect other than the 40A fuse? We only pulled this fuse but still have the noise.

The 40A fuse kills the power to the compressor as far as I know. We pulled that fuse, the question is what else are we supposed to disconnect to get rid of the solenoid noise coming from the rear?

rkw77080

There are 2 "AIRSUS" fuses you need to pull.


The 40A fuse is in the engine bay near the battery (which you already pulled), the 20A fuse is in the Driver-Side fuse box (see fuse circled in red in picture below).

restor2

Thanks a lot for the response, I really appreciate it.

We didn't pull the 20A under the dash because we believe it would cause the AFS light to go on on the dash.

Post #130 here
https://www.clublexus.com/forums/ls4...n-infos-9.html

Describes the issue.

I am wondering if perhaps there is another way to get rid of the solenoid noise. Pulling the 20A AIRSUS apparently does get rid of the solenoid noise, but also causes the AFS light to go on. This is undesirable.

Is there is a way to disable the rear height control valve (am assuming that this is what is making the noise) without causing the ECU to trigger the red triangle/VSC light or the AFS warning light?

Thanks in advance.

rkw77080

Apparently the 20A "AIRSUS" fuse covers other functions...

Refer to diagram below, I've circled the solenoids locations. You can try unplugging the power/signal wires from the solenoids and see if the ECU will complain.

Lavrishevo

iTrader: (1)

So, the height sensor tiggers the solenoid in an effort to pump up an air shock. If you re-adjust the height sensor it should not engage the solenoid. Another option to avoid any errors on the dash.

restor2

Thanks very much, really really helpful.

Thanks. Do you have the procedure to adjust the rear height sensor (i.e. that eventually controls the rear height control valve)? Have looked around, all I have found is this:

"If you study the rear suspension with it up in the air you can see the height sensors. You may try adjusting them to lower the car. Remember to lengthen the rod to make the car think it is higher and it should compensate and lower the car. Also, to keep it even I would count the number of turns and do both sides the same. "

Thanks in advance.

rkw77080

Here's the height adjustment procedure. You have two sensors for the front and two for the rear...

restor2

Gentlemen:

Thanks for all your help, it is appreciated very much.

If this were your car, would you try the rear sensor adjustment first (rather than disconnecting power to the height valve)? If so, and if the rear valve clicks on and off only at slow speed, would you raise the rear sensor height?

In other words, under item 8 in the PDF provided:

8. ADJUST REAR VEHICLE HEIGHT
(a) The rear vehicle height can be adjusted by moving the installation position of the link on the lower arm.
When the link is moved 1 mm (0.04 in.), the vehicle height is adjusted by about 2 mm (0.08 in.).

Would your guess be that we should lengthen the installation portion of the link? The computer thinks it is in regular height mode, the suspension was changed to sport, since this is a totally stock OEM install there are no significant adjustments for height in the stock (non-air) sport suspension, so it seems that the car has to be led to believe that the body is higher than it is, which means lengthening the installation position of the link in #8.

Does that seem right?

Thanks in advance.

Lavrishevo

iTrader: (1)

You should not have to modify anything on the height sensors. I would try to adjust the sensor so it sits in the middle of the range. This should stop the solenoid from engaging. You can also try removing power to the solenoid itself but as mentioned the air suspension computer probably won't like this. I would go the sensor route as this is the normal way it's done.

restor2

OK so if I've got this right, since I have the noise in the rear, this is what should be done

1) Adjust the two ride height sensors which are attached to the rear suspension. There are two of these, one per wheel. They are to be turned to lengthen them. The part number for the left rear is 89408-50060 (#14 on the attached picture).

The above is preferred. The other alternatives (if the above doesn't work) are to:

2) adjust the position of the link on the lower arm for the rear in the 'Height Adjustment.pdf' pdf provided above.

3) disconnect the rear height valve.



?




Thanks in advance.