Rear Suspension Problem...


02AfMe
06-27-2006, 06:05 PM
The rear end of my 2002 Envoy SLT (49,000 miles) recently dropped, without warning, and will not reset to it's normal positioning. It seams the ECAS system has failed; my gut tells me the compressor has gone bad. Have others experienced similar problems? Any ideas on what might have caused this and/or how to best fix the problem?

I am currently overseas and took the Envoy to a local repair shop that's familiar with American cars and GMC's in particular, but they didn't seem to know what caused the suspension to drop. However, the mechanic somehow reinserted some air into the system (the car now at least sits level), but the ride is still not as smooth as it should be. Any advice on how to solve this issue would be much appreciated!!!

02AfMe
07-03-2006, 05:39 PM
Has anyone experienced this problem? I'm still guessing it is the compressor that has failed, but this has not been confirmed. Any ideas on how much a new compressor cost or would I need to buy a whole new rear suspension system? I welcome any comments...

maxwedge
07-03-2006, 07:16 PM
Has anyone experienced this problem? I'm still guessing it is the compressor that has failed, but this has not been confirmed. Any ideas on how much a new compressor cost or would I need to buy a whole new rear suspension system? I welcome any comments...
Could be the leveling sensor, a blown fuse for the compressor, bad connections to the sensor or the compr. This will be tough to fix overseas, alldata.com has an online manual for diagnostics and repair .

SouthernGirlAlso
08-09-2006, 11:27 AM
I am having a similar problem with my 2002 Envoy SLT. I now have over 100,000 miles. My problem started around 80,000+ miles. The rear of my Envoy will squat. As soon as I start the ignition, the air compressor will inflate the air bags and the ride is fine. I have taken it to the dealership several times and left it all day but they can not find what is wrong with it. Ironically, it will never deflate when it is at the dealership. I even took pictures to prove I was not making this up. Now, there is 1 other vehicle that is doing the same thing. Does anybody know what is causing this to happen? They put in a new pumb but it is still happening.

maxwedge
08-09-2006, 12:44 PM
I am having a similar problem with my 2002 Envoy SLT. I now have over 100,000 miles. My problem started around 80,000+ miles. The rear of my Envoy will squat. As soon as I start the ignition, the air compressor will inflate the air bags and the ride is fine. I have taken it to the dealership several times and left it all day but they can not find what is wrong with it. Ironically, it will never deflate when it is at the dealership. I even took pictures to prove I was not making this up. Now, there is 1 other vehicle that is doing the same thing. Does anybody know what is causing this to happen? They put in a new pumb but it is still happening.
Welcome to AF, this is caused by a slow leak in the leveling system, could be anywhere from the pump to the rear lift shocks.

Chriznat20@msn.com
09-28-2006, 10:08 AM
Not necessarily true. There is a pressure relief valve in the ECAS compressor. It is signalled on/off by the ECAS module, and if it is worn/stuck open, the air would just continue to leak out. However, at 100,000 miles it would be a great time to check the operation of the compressor and replace if faulty, and also check all air lines.

Welcome to AF, this is caused by a slow leak in the leveling system, could be anywhere from the pump to the rear lift shocks.

maxwedge
09-28-2006, 02:56 PM
Not necessarily true. There is a pressure relief valve in the ECAS compressor. It is signalled on/off by the ECAS module, and if it is worn/stuck open, the air would just continue to leak out. However, at 100,000 miles it would be a great time to check the operation of the compressor and replace if faulty, and also check all air lines.
So this isn't a slow leak in the system as was stated?

GAR2
10-29-2007, 03:48 AM
I have the same problem with my '02 Envoy. After taking the vehicle to the dealership to have a code read ( speed sensor in the rear end going bad). The Envoy sat down on the axle in the rear and although the compressor runs for a few second after starting and then shuts off as before, the rear bags never inflate. Can anyone provide me with pictures/directions on locating any fuses, relays, valves, compressor or leveling module that could be causing this problem? I am willing to pay but I do not want to go back to the same dealership that denies that their checking the codes could have caused this problem.

GAR2
11-01-2007, 02:37 PM
As you might have already read on the thread, I am experiencng a similar problem with my 02 Envoy. I have not yet figured out how to test the compressor off the vehicle but I did locate it and remove it. It actually was not that hard to access as it is on the outside of the frame rail underneath the rear passenger quarter panel. Only a couple of 9/16ths bolts hold the bracket that the compressor is mounted on to the frame then it is just a matter of removing the air lines and power plugs to remove it. Always remember to note where each air line goes back or take a picture before removing them.

I decided it was the compressor because I connected the hose and gauge to the rear port in the rear of the vehicle and turned the pump on and let it run for several minutes. The pump never built any pressure according to the gauge so this makes the theory of the internal relief valve failue plausible.

To get a replacement compressor overseas, go to junk yard dog on the internet and post your request. Someone on the web will have one and most ship all over the world with at least a 30 day warranty although you would need to check with whoever you buy it from for their individual policy. Good Luck!

erinmahoney04
06-06-2008, 02:56 PM
We had the same problem. Crossed our fingers and bought a new compressor online gmbuyparts.com ($350). Husband installed it and it fixed it immediately.
:cool:

maxwedge
06-06-2008, 03:03 PM
Welcome to AF, please check the dates on the the threads this is way too old, thanks.

Add your comment to this topic!