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Our 2008 Chevy Uplander has an auto levelling system, where if a certain amount of weight is placed in the rear, it will pump air in, or take it out of the rear suspension to keep the vehicle level. My wife recently hit a BIG pothole, and it seems since then the sensor has gotten stuck in the position where it thinks the vehicle is weighted down in the rear, and is pumping a bit more air into it each time we start the vehicle.

At first it wasnt too bad, we could feel the rear suspension was a bit stiffer than usual but it was driveable. After troubleshooting it a bit more ourselves, the suspension has been pumped up to the max. I can hear the compressor kick on for a few seconds each time i start the vehicle. The compressor does not run constantly, just those few seconds (like is usually would to level the vehicle before driving). There is so much air in it now that the rear will not move down at all, making for a very rough ride. you can also see how high the rear end is in the air when looking at the van.

We have it scheduled to go into the dealer to have it looked at, but before it goes in I wanted to see if anybody has had any experience with this sort of issue. To me it just sounds like a sensor needs to be reset/unstuck. Is there something i can check underneath without having to dig out too many tools and start taking things apart, or is this a fairly complex mechanism? Short term it would be nice to drain a bit of the air that is trapped in the system for a little relief while we are driving it in the meantime. I have already removed the fuse for the level control and replaced it to see if that would reset the system, but didn't seem to have an impact. I am pretty sure there is a mechanism that attaches to the body and the suspension that controls this and its likely gotten itself stuck.

Any pointers on this one would be a big help!!

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I would imagine there is a mechanical linkage attached to the axle and bodywork with a sensor to measure the angle between them. Chances are, as you suggest, either it has got stuck or damaged, or something is wedged in it stopping it from moving correctly. Can you get under the back of the vehicle? If so, you may be able to identify the mechanism and there is a good chance that any damage or obstruction will be visible, and you may be able to rectify it.

Alternatively, you might be able to disconnect the sensor and fool it into thinking the system is unloaded. With an older vehicle, this would be quite easy (either short or open-circuit the connector), but I suspect yours will be too new for that to work, as most modern vehicles run such sensors off the central computer.

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