Service Air Suspension...Again!!! HUMTECH

[14u2nv2]

Started getting the "Service Air Suspension" message intermittently, but the air suspension still inflated and maintained ride height when the truck was running.

Sometimes (but not always), when the truck was parked overnight, the air suspension would deflate overnight, but would re-inflate as soon as the truck was started.

A few days ago, whenever I started the truck, the compressor would run for about 30 seconds and shut off and the "Service Air Suspension" message came on without raising the suspension (sitting on the bump stops). Every time I start the truck it does the same thing, and the compressor only runs for 20-30 seconds and does not raise the suspension (either side).

The compressor seems to be working OK and the air port/hose work when I switch the air compressor on with the switch in the rear of the truck.

I bought new air springs, since the truck's a 2003, and figured it's about time to replace them anyway. When I pulled the driver side air spring, I checked it for leaks and it had a very tiny leak--not enough to cause the problem, so I checked the air line while the compressor was running and no air was coming out of the line on the driver side.

So I bought a new driver side height sensor and still no luck. Nothing has changed and I still have the same problem. No air coming out of the driver side air line and the compressor shuts off after a few seconds.

My local dealer, that used be a Hummer dealer is now just a Cadillac dealer and seems to be a little clueless. The nearest hummer dealer is about 30 miles away and I don't want to drive the truck too much on the bump stops.

I know that the ride height needs to be calibrated after a sensor change, but is it possible that it would not work at all with a new sensor until calibrated?

I can get a new compressor for about $400 and am tempted to do this, but that won't solve the problem if it's a calibration issue.

Any other tricks to dianose this?

Any help is greatly appreciated,

John