Bad Height Sensor or Replace Air Suspension?
03-09-15, 04:08 PM
#1
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Bad Height Sensor or Replace Air Suspension?
A few months ago, I got an error message on the dash display indicating a height error on my '02 UL with 135k.. Turns out the left front tire was extremely low due to a nail. After repair and remounting, the error message disappeared and has not reappeared.
A month later, the rear end is sagging and I notice a slightly rough ride from the rear suspension. I took it to a trusted dealer a few days ago to check the air suspension. He indicated no noticeable leaks because the air shocks were clean. He connected a diagnostic computer and said that the error code showed the rear height sensor were bad. He suggested replacing both rear sensors.
I don't mind doing it if it solves the problem. My fear is that money is spent maintaining the air suspension is wasted because even if this does fix it (I am skeptical that the error code is left over from the tire issue a few months ago), a air shock or the compressor will soon fail. A better approach is just to replace the air with steel. My problem is finding someone to do the work in the Detroit area. I am open to any comments or suggestions, thanks.
A month later, the rear end is sagging and I notice a slightly rough ride from the rear suspension. I took it to a trusted dealer a few days ago to check the air suspension. He indicated no noticeable leaks because the air shocks were clean. He connected a diagnostic computer and said that the error code showed the rear height sensor were bad. He suggested replacing both rear sensors.
I don't mind doing it if it solves the problem. My fear is that money is spent maintaining the air suspension is wasted because even if this does fix it (I am skeptical that the error code is left over from the tire issue a few months ago), a air shock or the compressor will soon fail. A better approach is just to replace the air with steel. My problem is finding someone to do the work in the Detroit area. I am open to any comments or suggestions, thanks.
03-10-15, 05:53 AM
#3
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I second starting out with used parts from the salvage yard. The LS430 is an old enough vehicle that finding used air suspension parts is becoming easier and easier. I wouldn't go straight to steel unless you have more than a single air strut failed. I found a compressor for $200 shipped because mine has 220k on it, and the exhaust solenoid is sticking. I'm still on the fence converting to steel.
03-13-15, 10:32 AM
#4
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I decided to replace the height sensor. So far, so good. The rear end has returned to the proper height and the smooth ride is back. Hope this post isn't a jinx. For now, everything is working great
03-13-15, 02:24 PM
#5
as I'm in the market for a UL and have studied oh i don't know maybe 50+ UL maintenance histories, I can tell you that at least 90% of them have had at least one height sensor replaced by the dealer, and many have had multiples. Pretty surprising actually. Not sure why this part seems to fail but it sure seems to.
03-13-15, 05:35 PM
#6
as I'm in the market for a UL and have studied oh i don't know maybe 50+ UL maintenance histories, I can tell you that at least 90% of them have had at least one height sensor replaced by the dealer, and many have had multiples. Pretty surprising actually. Not sure why this part seems to fail but it sure seems to.
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03-15-15, 09:53 AM
#8
Do the height sensors have to be programmed after install? A little confused on how they work since i noticed they dont connect with any wires. Are they wireless or? How does the car receive information from them to know when to lower and raise?
10-22-15, 09:45 AM
#11
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because I am getting conflicting answers; makes it hard to act on them because then I am stuck. I am trying to filter out the wellwishers from the ones who actually have done it. Most of them do not answer my questions, you get only tidbits that require more questions
What exactly are the heightsensors do once the AS is disconnected?
Should I disconnect the ECU also? Leave the air compressor in or remove it?
What exactly are the heightsensors do once the AS is disconnected?
Should I disconnect the ECU also? Leave the air compressor in or remove it?
10-22-15, 10:18 AM
#12
There is an air suspension ecu. If you remove it the car will not be happy. If you remove the height sensors the car will not be happy. It will not affect drivability but you will have warnings on your dash.
The height sensors do exactly what their names says they do. Engage the air compressor to raise the level of the car. Obviously, if you disable the compressor it will not be engaged. Pulling the fuse, physically disconnecting it makes no difference.
If you remove the height sensors the air suspension ecu sees the errors and puts a warning on your dash that never goes away. So, long story short. Just kill power to the air compressor and leave the height sensors alone. This is all you have to do. It's really not complicated.
The height sensors do exactly what their names says they do. Engage the air compressor to raise the level of the car. Obviously, if you disable the compressor it will not be engaged. Pulling the fuse, physically disconnecting it makes no difference.
If you remove the height sensors the air suspension ecu sees the errors and puts a warning on your dash that never goes away. So, long story short. Just kill power to the air compressor and leave the height sensors alone. This is all you have to do. It's really not complicated.
10-22-15, 11:36 AM
#13
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thank you
finally a clear answer,
so what exactly are the height sensors doing - level the lights when I have a full trunk and the lights would shine upwards? Adjust maybe a sagging corner?
If the Bilsteins keep the car level would the height sensors still be actively levelling any possible discrepancies?
How do I understand the sentence: physically it does not make any difference?
finally a clear answer,
so what exactly are the height sensors doing - level the lights when I have a full trunk and the lights would shine upwards? Adjust maybe a sagging corner?
If the Bilsteins keep the car level would the height sensors still be actively levelling any possible discrepancies?
How do I understand the sentence: physically it does not make any difference?
Last edited by semar; 10-22-15 at 11:39 AM.
10-22-15, 12:53 PM
#15
Physically remove the compressor or physically remove the power cable to the unit. Makes no difference.
The height sensors detect the height or amount of air in the bag of the air shock and tell the compressor to turn on to fill the airbag. Or do the opposite. Let air out.
The height sensors detect the height or amount of air in the bag of the air shock and tell the compressor to turn on to fill the airbag. Or do the opposite. Let air out.