Recently, my 2000 Expedition with 4 wheel LLS has been displaying the "CK SUSP" indicator after about an hour on the highway. When this indicator is displayed, the rear looks like like the air springs have been jacked up to their maximum height (the front looks normal).

The suspension eventually returns to its normal height when I turn the engine off and the warning light never come on during short trips.

Could it be the rear ride height sensor? The diagnostic fee to read the fault codes is almost as much as that part, so I might take a chance and just replace it. Is there another way to diagnose the problem?

Thanks.

 

The LLS seems a little complicated. There are lots of posts on it. There is a control module under the dash somewhere and a relay near the horns (RF). I too am having issues (my 98 Nav 4x4) is leaning to the left (about 1" lower than the right side). There are 2 height sensors, one above rear axle (center) and one on LF wheel near the steering column. I have seen posts where what you would think is the problem is the sensor and it's not the culprit, in fact, a different part that has to be changed. I have yet to find a post that describes normal operation of the LLS system. The rear sensor is easy to change and a trip to the bone yard may fix your problem with minimal cost. Curious to know what you find. Be sure to post the cure.....