Last week I had an adjustment done to my factory air suspension on my '02 UL. I had done the lowering method years ago by adjusting the sensor rods, and I shortened the front rods too. It has always been a pain in the butt to get the car leveled out though. I took my car to a new DIY garage here in Miami and had it adjusted with the help of the owner who also has an '04 UL. He had figured out a method to get the suspension properly leveled. Using a very expensive software program called Auto Enginuity, he hooked up his laptop to the car and displayed the suspension height sensor readings. As you can see in the pic my front sensors were fairly similar but the rears were way off, one high and one low. With the car on a 4-post lift he used tie straps to set the front suspension at equal height on both sides, observed the readings on the computer, then adjusted the sensor rods to match. I am still unclear as to exactly what the procedure is since for most of the time I was in the car cycling the suspension up and down with the Hi-Lo switch. Apparently it helps greatly to know that the front sensors control the left-right balance of the entire car. The rear sensors control the height of the rear only, and it is determined by an average of the two rear sensor positions. Also the height of the rear determines the overall ride quality of the car, the lower it is in the rear the stiffer the entire suspension.

 

Great info here. I wonder if Techstream gives any of this readout. I don't remember seeing this.

 

Interesting. When I first attempted the height adjustment by adjusting the rods, the passenger side would lower and the driver side wouldn't. I took the driver side rod out entirely to see how low the car would go. When I put the rod back in, the driver side looked like it was now even higher than stock height, even though the rod was in the lowest position it would go. I had to end up heightening the rod on the passenger side to match the driver side because the passenger side was stock high and driver side was very high (about 1.5-2 in higher). Now my car looks kinda ridiculous. Very high in the front, normal height in the rear. I think I will just go ahead and buy the air controller. Hopefully it can help me level my car out so I can at least drive with all the sides at their proper stock height. Then lower it when I park

 

On TIS Techstream you can see all sensors value and make some tests. Example you can lower one wheel (it will go up after couple of seconds).